B.E. First Semester (Applied Physics) (C.B.S.) APPLIED ...

B.E. First Semester (Applied Physics) (C.B.S.) APPLIED PHYSICS

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Question Bank

UNIT-1 (Wave Optics) Question Number

Questions with Options Answer Key

1 The phenomenon of redistribution of light energy when there is superposition of light waves coming from two or more coherent sources is called__________.

a) Diffraction b) Interference c) Reflection d) Attenuation

B

2 In destructive interference, the path difference between the two reflected waves should be equal to_______

a) 2n

b) (2n+1)

c) (2n+1) λ

d) n

C

3 In constructive interference, following is not the path difference between the two reflected waves should be equal to_______ a) 2n𝛌 b) (2n+1)𝛌

c) (2n+1) 𝛌

𝟐

d) n𝛌

D c

4 The intensity of the wave is directly proportional to the _____ a) Under root of energy of wave b) Square of the amplitude of wave c) Twice the frequency of wave d) none of above

B

5 Following is the method for obtaining interference pattern in thin films (a) by division of amplitude (b) by division of wave front (c) both of above (d) None of the above

A

6 Which of the following is the correct answer? (a) OPD = µ x GPD (b) OPD = µ + GPD (c) OPD = µ - GPD (d) OPD = µ /GPD

A

7 A film is said to be thin when its thickness is of the order of ________ of incident light.

(a) time period (b) wavelength (c) angular frequency (d) velocity

B


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8 The thickness of the wedge-shaped thin film______ away from point of contact O. (a) remains constant (b) increases (c) decreases (d) none of the above

B

9 In case of wedge-shaped thin film, the fringes are ________

(a) Straight. (b) parallel (c) equidistant (d) All of the above.

D

10 In case of wedge-shaped thin film, the fringe width β _______with increasing wedge angle θ.

(a) remains constant (b) increases (c) decreases (d) none of the above

C

11 In Newton’s rings experiment, the diameter of the dark ring is proportional to

(a) √𝑚

(b) √

(c) √2𝑚

(d) √2𝑚 + 1

A

12 In Newton’s rings experiment, plane glass plate is inclined at an angle of ____ with respect to incident rays coming from the source.

(a) 45o (b) 95o (c) 180o (d) 25o

A

13 In Newton’s rings experiment, path difference of the interfering reflected rays at the point of contact of the lens with a glass plate, is ________

(a)

(b) n𝜆 (c) (2n+1) 𝜆 (d) 2n𝜆

A

14 The coating on the glass lens of suitable thickness of material which is used to suppress reflection from the lens surface is called _____coating. (a) antireflection (b) aquadag (c) nickel (d) copper

A


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15 The diameter of mth dark ring in Newton’s rings experiment is given by ---------------

(a) √𝑚𝜆𝑅

(b) ( )λR

(c) 2√𝑚𝜆𝑅.

(d) 2 ( )λR

C

16 The thin film can act as AR coating if it meets one of the following conditions:

(a) The waves should have equal amplitudes (b) The waves reflected from top and bottom of the film should be in phase (c)The waves should have different amplitudes. (d) None of these

A

17 In Newton’s rings experiment if a white light is used instead of monochromatic light then ______

(a) The colored rings are seen near the point of contact. (b) General illumination is observed over the region (c) The rings will not be observed at all (d) The region will be divided into different color, VIBGYOR

A

18 The optical thickness of anti -reflection coating should be one _____ of the wavelength.

(a) eighth (b) fourth (c) third (d) tenth

B

19 A point source of light produces_____

(a) Cylindrical wave front (b) Plane wave front (c) Spherical wave front (d) Wave normal

C

20 An Extended source of light produces (a) Cylindrical wave front (b) Parallel to the wave front (c) Plane wave front (d) Spherical wave front

A

21 The diffraction phenomena is noticeable only when -----

(a) The slit width is large (b) The source is polychromatic (c) The slit width is of the order of wavelength (d) An object is transparent

C


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22 The condition for maxima for interference in thin film is --------

(a) 2μtcosr = (2m+1)

(b) 2μtcosr = mλ

(c) 2μtcosr =

(d) 2μtcosr = 0

A

23 The distance between two successive dark or bright fringes is called as ________.

(a) Angle of wedge (b) Fringe width (c) apex (d) thickness of thin film

B

24 For a better interference pattern, Plano convex lens used in Newton’s rings experiment should be__________

(a) of large radius of curvature (b) small radius of curvature (c) very thick (d) very thin so as to get proper rings

A

25 In Newton’s rings experiment the fringes are crowded away from the center, the reason is______

(a) the lens has small radius of curvature (b) monochromatic light is used as source (c) Diameter of a ring is directly proportional to square root of ring number (d) All of the above

C

26 The fringes of equal thickness are observed in a thin glass wedge of refractive index 1.52. The fringe spacing is 0.1mm and wavelength of the light is 5893A0 . The angle of wedge is ______

(a) 0.110 (b) 1.94 x10-1radian (c) 5.150 (d) 1.0960

A

27 In Newton’s ring experiment we get the diameter of the 10th ring as 0.5cm, the wavelength of the light in air is 6000A0, how much is the radius of curvature of the lens.

(a) 104 cm (b) 10.4m (c) 41.66cm (d) 83.3cm

A

28 Find the thickness of water film with refractive index of 1.33 formed on a A


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glass window - pane to act as non-reflecting film. Given λ= 5500 Å a)1033 Å b)5033 Å c)8094 Å d)2894 Å

29 A glass of microscope lens is coated with magnesium fluoride (μ=1.38) film to increase the transmission of normally incident light of wavelength 6800Å. What is minimum film thickness needed for optimum result? (a) 1231.88 Å (b) 1851.88 Å (c) 1471.88 Å (d) 3231.88 Å

A

30 In a Newton’s ring experiment, the diameter of the 15th ring was found to be 0.59 cm and that of the 5th ring was 0.336 cm. If the radius of the plano-convex lens is 100 cm. Calculate the wavelength of light used.

(a) 5.8801𝑋10 𝑚 (b) 12.8801𝑋10 𝑚 (c) 8.8801𝑋10 𝑚 (d) 10.8801𝑋10 𝑚

A

31 The shortest distance travelled by light in air vacuum is known as _______

(a) Optical path (b) Geometrical path (c) Young’s path (d) Lloyd’s path

B

32 The condition for minima for interference in thin film is --------

(a) 2μtcosr = (2m+1)

(b) 2μtcosr = mλ

(c) 2μtcosr =

(d) 2μtcosr = 0

B

33 In interference: (a) There is loss of energy in greater amount (b) There is redistribution of energy (c)There is loss of energy in lesser amount (d) None of these

B

34

Shape of interference fringes will be decided by collection of all points in thin film at which (a) Thickness of the film is constant (b) Material used for the thin film (c) Thickness of the film is variable (d) All of the above

A


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35

Two waves of same frequency and amplitude having phase difference of180°, which of the following is correct? (a) They interfere constructively (b) Their amplitudes are added (c) Destructive interference occurs (d) All of the above

C

36 What causes the bright coloured patterns sometimes seen on wet streets covered with a layer of oil? (a) Diffraction and polarisation (b) Interference (c) Refraction and diffraction (d) Reflection and interference

B

37 When we introduce a liquid drop between lens and glass plate, the radius of rings (a) increases (b) Decreases (c) No change (d) Depends on wavelength of light used

B

38 When light is incident normally on the surface of thin film,what will be angle of incidence and angle of reflection (a) i=90°,r=0° (b) i=r=0° (c) i>r (d) i=r=90°

B

39 Interference can be used to test (a) Flatness of the surface. (b) Type of curvature of the object (c) Both of the above (d) None of the above

C

40 When the path difference between the two light waves is integral multiples of wavelength, then the waves are said to be? (a) Out of phase (b) In phase (c) Unaffected (d) Diffracted

B

41 Diffraction is defined as (a) Superposition of primary wave fronts from coherent sources (b) Superposition of primary wave fronts from incoherent sources (c) bending of the light around the corners of obstacle (d) Interference of light

C

42 What is a diffraction pattern? (a) A pattern of intensity variation consisting of equal-width maxima and minima (b) A pattern of intensity variation consisting of unequal -width maxima and minima

B


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(c) A uniform intensity illumination (d) A pattern of zigzag variation

43 In Newton’s rings experiment, ring at the point of contact in case of reflected light is always (a) bright (b) dark (c) Colored (d) None of these

B

44 In Newton’s ring experiment, fringe at the apex in case of transmitted light is (a) bright (b) dark (c) colored (d) None of these

A

45 A phase change of π radian is equivalent to a path difference of (a) λ /4 (b) λ /2 (c) λ /3 (d) λ /8

B

46 Wedged shaped thin film is said to be a film of ________ thickness. (a) Uniform (b) Varying (c) Constant (d) None of these.

B

47 Plane parallel thin film is said to be a film of__________ thickness. (a) Uniform (b) Varying (c) Random (d) None of these.

A

48 In Fresnel’s diffraction the source and the slit are at ______ distance from the obstacle.

(a) Finite (b) Infinite (c) Random (d) None of these

A

49 In Fraunhofer’s diffraction the source and the slit are at ______ distance from the obstacle.

(a) Finite (b) Infinite (c) Random (d) None of these

B

50 Resolving power of an optical instrument is given by (a) λ/dλ (b) λ/dθ (c) λ/dx (d) λ/dt

A

51 The method by which close objects can be seen separately is called as (a) Diffraction (b) Resolution

B


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(c) Refraction (d) Reflection

UNIT-2 (Quantum Mechanics)

Question Number


1 In Compton effect-------- gets scattered. (a) proton (b) electron (c) X-ray photon (d) deuteron

C

2 In Compton effect the unmodified radiation results from the interaction of photon with (a) valance e- (b) tightly bound e- (c) nucleus (d) none of the above.

B

3 Which one of the following statements is true? (a) Photon is electrically positive (b) Photon is electrically neutral (c) Photon is electrically negative (d) All above statements are true.

B

4 Davisson & Germer Experiment confirms_______ a. Particle nature of electron b. Wave nature of proton c. Wave nature of photon d. Wave nature of electron

D

5 In Compton effect the intensity of the unmodified radiation goes on increasing with (a) Increasing atomic number (b) Decreasing Atomic number (c) Increasing frequency of incoming Radiation (d) Increasing dimensions of target

A

6 In Compton effect, following equation is for law of conservation of___________

𝒉

𝝀+ 𝟎 =

𝒉

𝝀′𝒄𝒐𝒔𝜱 + 𝑷𝒄𝒐𝒔𝜽

(a) Energy (b) Momentum (c) Force (d) Pressure

B

7 Compton shift depends on (a) wavelength of incident radiation (b) scattering angle (c) velocity of incident radiation (d) All of the above.

B

8 Compton scattering is experimentally observable for photons of (a) high energy (b) low energy (c) visible light (d) both high and low energy

A


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9 De-Broglie equation states the: (a) dual nature of matter (b) particle nature of light (c) wave nature of light (d) none of these

A

10 De-Broglie wavelength of a body of mass m and kinetic energy E is given by (symbols have their usual meanings):

(a) λ = √

(b) λ= 2mE (c) λ= √2𝑚𝐸

(d) λ= √

A

11 Complete the following statement: According to the de Broglie relation, the wavelength of a "matter" wave is inversely proportional to:

(a) Planck's constant (b) the force of the particle (c) the momentum of the particle (d) the frequency of the wave.

C

12 Quantum of light is known as _____ (a) electron (b) neutron (c) photon (d) proton

C

13 Which of the following two particles interact in Compton scattering? (a) photon and electron (b) proton and electron (c) neutron and electro (d)proton and neutron

A

14 Photons are electrically, (a) positively charged (b) negatively charged (c) neutral (d) strongly charged, may be positive or negative

C

15 Dual nature of matter was proposed by a) de-Broglie b) Planck c) Einstein d) Newton

A

16 Of the following properties, the photon does not possess (a) rest mass (b) momentum (c) energy (d) frequency

A

17 The momentum of a photon of wavelength λ is (λ= h/p, p=h/ λ=h/(c/ν)=h ν/c [ν=c/ λ, λ=c/ ν] (a) hλ (b) hν/c (c) λ/h (d) h/cλ

B

18 Which of the following supports existence of matter waves? (a) X-ray Diffraction Experiment (b) Davisson- Germer Experiment (c) Photoelectric Effect (d) None of these

B

19 The expression for Compton Shift (where symbols have their usual meaning) D


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is given by:

(a) Δλ = (1 − 𝑐𝑜𝑠𝜙) (b) Δλ = (1 − 𝑐𝑜𝑠𝜙)

(c) Δλ = (1 − 𝑠𝑖𝑛𝜙) (d) None of these

20 The energy of a photon ---------

a) Varies directly with frequency b) Same for all frequencies c) Varies inversely with frequency d) None of the above

A

21 The De-Broglie wavelength of a particle of mass ‘m’ moving with velocity ‘v” is given by :

(a) λ = (b) λ= hmv (c) λ = (d) λ =

A

22 Matter waves are (a) transverse mechanical waves (b) electromagnetic waves (c) longitudinal mechanical waves (d) none of the above

D

23 The de-Broglie hypothesis reveals (a) wave nature of protons only (b) wave nature of all material particles (c) wave nature of electrons only (d) wave nature of alpha particles only

B

24 In Bohr’s Quantization following quantity____ is quantized. (a) Position (b) Frequency (c) Angular momentum (d) Angular Frequency

C

25 An electron to stay in nth orbit of atom, the waves associated with an electron in an orbit should satisfy condition_______ (a) 2πrn =nλ (b)3πr=nλ/2 (c)4πr=nλ/3 (d) 2πr=λ/2

A

26 In Compton scattering, wavelength of scattered X-ray photon is 0.3032 Å find the energy of scattered photon in eV.(Consider, h= 6.63 x 10-34J.sec and c=3 x108m/sec., hc = 12400 eV) (a)90877.09 eV (b)40897.09 eV (c)60897.99 eV (d)50897.79 eV

B

27 The de Broglie wavelength of α-particles accelerated through a potential difference of 100 Volts is given by ________ (Consider mass of α-particles= 6.68x10-27Kg and its charge=3.2x10-19C) (a) 1.014 x 10-12 m (b) 1.014 x 10-10 m (c) 1.014 x 10-9 m

A


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(d) 1.014 x 10-11m 28 In Compton collision, the incident radiation of wavelength 1.087A0 is

scattered from a scatterer at an angle of 300 then the wavelength of scattered photon is given by, (a) 1.09 A0 (b) 2.90 A0 (c) 4.33 A0 (d) 6.23 A0

A

29 The de-Broglie wavelength associated with 2000 kg car having a constant speed of 25 m/s is given by ___________ (Consider h= 6.63x10-34J.sec) (a) 1.326 x 10-38 m (b) 8.27 x 10-37 m (c) 7.89 x 10-9 m (d) 6.80 X 10-2 m

A

30 The de Broglie wavelength of the orbital electron of hydrogen atom, given that its energy is 13.6eV is given by: (a) 3.33 A0 (b) 1.21 A0 (c) 5.52 A0 (d) None of these

A

31 Compton effect cannot be observed with visible light because

(a) Compton shift is large (b) Visible radiations do not collide with free electron (c) Visible radiation has wavelength of the order of 5000Ao-7000Ao which is

very large as compared to Compton shift (d) None of these

C

32 In Compton effect, the Compton wavelength is given by------

(a) λf ; modified wavelength

(b) λc = = 0.0242 Ao

(c) λi ; unmodified wavelength

(d) None of these

B

33 In Compton effect the modified component results from the interaction of photon with (a) valance electron (b) loosely bound electron (c) nucleus (d) none of the above.

B

34 Matter waves are significant only for---- (a)

Macroscopic bodies (b)Stationary bodies

C


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(c)Microscopic bodies (d)None of the above

35 In Compton effect, following equation is for law of conservation of_________

hν + moc2 = 0 + (𝑝 𝑐 + m 𝑐 )

(a) Angular momentum (b) Linear Momentum (b) Energy (d) None of these

C

36 Matter waves are the waves associated with (a) electromagnetic waves (b) moving micro particles (c) are transverse waves (d) are longitudinal waves

B

37 Among the following particles moving with the same velocity, the particle having shortest wavelength associated with it is: (a) electron (b) Alpha particle (c) Both of them

(d) None of above

B

38 If accelerating voltage is increased the wavelength associated with moving micro particle will------ a) Increases b) Decreases c) Remain constant d) None of above

b

39 The de- Broglie wavelength of an electron whose speed is half that of light is (a) 3.6 x 10- 12 m (b) 4.8 x 10- 12 m (c) 4.2 x 10- 12 m (d) 6.11 x 10- 12 m

C

40 In Compton effect, we observe (a) Modified radiation (b) Unmodified radiation (c) Modified radiation and unmodified radiation (d) None of the above

C

41 de-Broglie’s Wavelength associated with electron accelerated through a potential V is given by

(a) λ =.

√ Ao

(b) λ =.

√ Ao

c)λ =√

Ao

d) λ =.

√ Ao

A


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42 In electron diffraction experiment, Davission and Germer used ….. to verify

the experimental value of λ 𝑖𝑛 Ao

a) Boyel’s law

b) Newton’s law

c) Bragg’s law of x-ray diffraction

d) Bethe’s law

C

43 Compton effect is significant in light elements because

a) more number of free electrons are available for interaction

b) more number of bound electrons are available for interaction

c) more number of photons are available for interaction

d) None of above

A

44 De Broglie wavelength cannot be observed for the following ------

a) Stone

b) Cricket ball

c) Chalk

d) All of the above

d

45 Justification of Bohr’s Quantization condition of angular momentum can be

justified using

a) de-Broglie’s hypothesis

b) Compton effect

c) Davission and Germer experiment

d) Bethe’s law

A

46 Compton effect is successfully explained by quantum mechanics by assuming

(a) electron which scatters is a free electron

(b) electron is initially at rest

(c) electron is micro particle

(d) (a) and (b)only

D


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47 Which of the following phenomenon can be explained by quantum mechanics? (a) Newton laws (b) Maxwell electromagnetic theory (c) Compton Effect (d) All the above

c

48 In high atomic number scattering element ,intensity of unmodified wavelength is high because------- a) Number of free electrons are more b) Number of photons are more c) Number of tightly bound electrons are more d) Scattered radiation is more

c

49 Compton shift is independent of a) Planks constant b) Wavelength of incident photon c) Rest mass of electron d) Speed of light

b

50 de-Broglie introduced the concept of wave particle duality for------ (a) material particles (b) sound waves (c) light waves (d) all of the above

A


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UNIT-3 (Wave Packet & Wave Equations)

Question Number


1 As per the Heisenberg Uncertainty principle, it is not possible to measure position and ________________ simultaneously with unlimited accuracy. (a) Angular momentum (b) Linear Momentum (c) Energy (d) None of these

B

2 Heisenberg’s Uncertainty Principle for measurement of energy and time is________ (a) ∆P∙∆θ ≥ħ (b) ∆E∙∆t ≥ħ (c) ∆P∙∆x ≥ħ (d) None of the above

B

3 ∆x (uncertainty in position) is related to ∆p (uncertainty in momentum) _______________ (a) Directly (b) Inversely (c) Proportionally (d) Adversely

B

4 Heisenberg Uncertainty Principle is significant for ______________ (a) Macroscopic particles (b) Microscopic particles (c) Daily life (d) All of the above

B

5 For a micro particle in an infinite potential wellthe allowed energy states are given by_____________

(a) En=n2 h2/4mL2

(b) En= n2h2/32mL2

(c) En= n2h2/16mL2 (d)En= n2h2/8mL2

D

6 Heisenberg Uncertainty principle is not significant in ____________ (a) Macroscopic particles (b) Microscopic particles (c) Atomic particles (d) None of the above

A

7 Wave function of a micro particle is ___________________ (a) Not associated with moving particle (b) Complex quantity. (c) Not normalized (d) None of the above

B

8 In an infinite potential well, potential energy of a micro particle (V) is _ (a) Zero (b) Maximum (c) Infinite (d) None of the above

A


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9 Moving particle is conceptualized as a ________ (a) Wave packet (b) Wave Density (c) Wave velocity (d) Uniform velocity

A

10 According to Normalization condition of wave function, if at all the particle exists, then total probability of finding the particle in space must be __________ (a) Zero (b) Unity (c) Infinity (d) Double

B

11 The normalized wave function must have ________ value (a) Infinite (b) Zero (c) Finite (d) None of above

C

12 The square of the magnitude of the wave function is called_________ (a) Current density (b) Probability density (c) Zero density (d) Volume density

B

13 A well-behaved wave function should be (a) Finite (b) Single valued (c) Continuous

(d) All of the above

D

14 What is the minimum energy possessed by micro particle in an infinite potential well? (a) Zero

(b) E =

(c) E =

(d) E =

D

15 The wave function of a micro particle in a one dimensional box is given by ____________

(a) 𝛹 (x) = 𝑠𝑖𝑛 𝑥

(b) 𝛹 (x) = 𝑠𝑖𝑛 𝑥

(c) 𝛹 (x) = 𝑠𝑖𝑛 𝑥

(d) 𝛹 (x) = 𝑠𝑖𝑛 𝑥

B

16 A mathematical function used to describe the propagation of the wave associated with a moving particle is called ________ a)Wave packet b)wave function c)wave velocity d)None of the

B


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17 Wave packet is a combination of infinite number of waves with same amplitude but of slightly different _______________.

(a) Masses (b) Spin (c ) Electrical nature (d) wavelengths

D

18 In Normalization condition sum of all probabilities must be ________ (a) Zero (b) unity. (c) double (d) All of the above

B

19 The wave packet has maximum amplitude at the centre and ____________ at end points. (a)Small (b)Zero (c)Nonzero (d)Infinite

B

20 A micro particle confined in an infinite potential well cannot be allowed to take _________ energy.

a) maximum b) minimum c)Zero d) Nonzero

C

21 The motion of atomic particles can be determined using ____________ wave equation. a) Einstein's b) Schrodinger’s c) Planck's d) All of the above

B

22 Uncertainty Principle is a consequence of ________ nature of particle a) Wave b) Particle c) Electric d) None of the above

A

23 The wave function Ψ which is single valued, finite and continuous is called _____ behaved wave function. a) Bad b) Better c) Well d) None of the above

C

24 Schrodinger suggested two important equations for the motion of matter waves called time dependent and ______________ independent equations. (a)Time(b)Position(c)Momentum(d)All of the above

A

25 For a micro particle confined to an infinite potential well of width ‘L’ then Ѱ(𝑥) = 0 for a) x≥L b) x< L c) 0<x<L d) None of the above

A


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26 An electron is traveling with the velocity 220 m/sec, measured to an accuracy of 0.005 %. Calculate uncertainty in position of it. (a) 0.105 𝑚 (b) 1.05 𝑚 (c) 10.05 𝑚 (d) 0.0105 𝑚

D

27 A proton is confined to a nucleus of radius 10-14 m. Uncertainty in its location is diameter of nucleus. Calculate the minimum uncertainty in velocity of the proton. (Given:The mass of proton is 1.67x10-27kg, Planck’s constant ‘h’ = 6.63X10-34Js)

(a) 3.14 × 10 m/𝑠 (b) 3.16 × 10 m/𝑠 (c) 3.14 × 10 m (d) 3.14 × 10 m/𝑠

B

28 Consider that an electron is confined to a box of length 10-10 m. Calculate the lowest energy of the system.(Given: Planck’s constant ‘h’ = 6.63X10-34Js) (a) 37.6 eV (b) 37.6 J (c) 73.5 eV (d) 73.5 eV

A

29 Calculate the minimum uncertainty in the velocity of an electron confined to a box of 10-8 m length.(Given: Planck’s constant ‘h’ = 6.63X10-34Js and mass of electron ‘m’ = 9.11X10-31kg.)

(a) 601.45 𝑚/𝑠 (b) 16015 𝑚/𝑠

(c) 11588.72 m/s (d)1161.45 𝑚/𝑠

C

30

Calculate the Zero-point energy for a particle in an infinite potential well for an electron confined to a 1 nm atom.(Given: Planck’s constant ‘h’ = 6.63X10-34Js and mass of electron ‘m’ = 9.11X10-31kg.) (a) 3.9 X 10-20 J (b) 4.9 X 10-20 J (c) 6.03 X 10-20 J (d) 6.9 X 10-20 J

C

31 Wave function ψ itself has no direct ______ and hence is not experimentally measurable.

(a) measurable value(b) physical significance (c) structure(d) None of above

B

32 The wave function Ψ is a ________

(a) Complex function (b) Imaginary function (c) Real function (d) All of above

A


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33 Schrodinger equation gives the mathematical representation of _____

(a) Presence of electron (b) Wave function Ψ (c) Matter wave (d) Sound wave

C

34 Quantized energy of particle trapped in one dimensional potential well is inversely proportional to

(a) Height of potential well H (b) Number of quantum states n (c) Charge of particle e (d) mass of particle m

D

35 Inside one-dimensional potential well of infinite depth, value of wave functionΨ is _____ (a) Zero (b) unity (c)not zero (d) infinite

C

36 Potential energy of the particle inside the one-dimensional potential well is ____

(a) V = 0 (b) V= 1 (c) V = ∞ (d) V ≠ 0

A

37 To find wave function and quantized energy of microscopic particle inside the potential well, we apply ____

(a) Schrodinger’s time dependent wave equation (b) Schrodinger’s time independent waveequation (c) Schrodinger’s time dependent and time independent waveequations (d) None of above

B

38 Quantum mechanically, if particle is trapped inside the potential well, then value of energy is__________.

(a) quantized (d) not quantized (c) Zero (d) None of the above

A

39 Energy of electron ______ when it is moving from lower energy state to higher energy state.

(a) Remains constant (b) Increases (c) Decreases (d) Tends to zero

B


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40 Probability density of an electron confined in a potential well of infinite depth is directly proportional to______

(a) The square of the magnitude of the wave function (b) The square root of the magnitude of the wave function (c)The square of the magnitude of energy (d) The square of the width of the well

A

41 A baseball (mass= 0.15kg) is traveling with the velocity 220 m/sec.Uncertainty in measurement of its velocity is 0.011m/sec. Calculate uncertainty in its position.

(a) 6.39×10-32m (b) 8.268 x 10-32m (c) 2.968 x 10-32m (d) 4.830 x 10-34m

A

42 An electron is confined to move in a one dimensional potential well of length 5 Å. What will be the quantized energy value for first state?

(a) 5.26 x 10-19 J (b) 9.23 x 10-19 J (c) 2.41 x 10-19J (d) 3.26 x 10-19 J

C

43 The time independent Schrodinger equation in one dimension does not include the parameter

(a) Energy E (b) Potential V (c) Force F (d) Mass m

C

44

The time dependent Schrodinger equation in one dimension does not include the parameter

(a) Planks constant h (b) Potential V (c) Mass m (d) Energy E

D

45 According to Heisenberg’s uncertainty principle if energy of particle measured accurately then there will be uncertainty in ____

(a) Time (b) Momentum (c) Mass (d) Velocity

A

46 According to Heisenberg’s uncertainty principle if angular position of particle measured accurately then there will be uncertainty in ____

(a) Linear Momentum (b) Energy (c) Angular Momentum (d) Time

C


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47 Find the uncertainty in the location of an electron moving with a speed 0.5 x 108 m/s if Δp = p.(Given: Planck’s constant ‘h’ = 6.63X10-34Js and mass of electron ‘m’ = 9.11X10-31kg.) (a) 0.986 x 10-11m (b)0.231 x 10-11m (c) 0.855x 10-11m (d) 0.67 x 10-11m

B

48 The uncertainty in the location of an electron confined to a box is 2Å. Calculate the minimum uncertainty in its velocity.(Given: Planck’s constant ‘h’ = 6.63X10-34Js and mass of electron ‘m’ = 9.11X10-31kg.) (a) 0.11 x 107 m/s (b) 0.96 x 107 m/s (c) 0.0895 x 107 m/s (d) 0.0579 x 107 m/s

D

49 Uncertainty Principle is a consequence of ________ nature of particle a) Wave b) Particle c) Electric d) None of the above

A

50 Find the lowest energy of an electron confined to move in a one-dimensional box of length8Ǻ.(Given: Planck’s constant ‘h’ = 6.63X10-

34Js and mass of electron ‘m’ = 9.11X10-31kg.)

(a) 9.424 × 10 J (b)8.415 × 10 J (c) 10.785 × 10 J (d) 12.498 × 10 J

A


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UNIT-4 (Crystal Structure)

Question Number


1 Amorphous solids have _______ structure.

(a) Regular (b) Linear (c) Irregular d) Dendritic

C

2 The crystal lattice has _________ arrangement.

(a) One-dimensional (b) Two-dimensional (c) Three-dimensional (d) Four-dimensional

C

3 The smallest portion of the space lattice is known as __________

(a) Lattice structure (b) Lattice point (c) Bravais crystal (d) Unit cell

D

4 -----------is a system of notation of planes within a crystal of space lattice.

(a) Space lattice (b) Crystalline (c) Miller indices (d) identical

C

5 The number of Bravais lattices is:

(a) 256 (b) 7 (c) 14 (d) 37

C

6 A unit cell that contains lattice points only at the corners is known as ___

(a) Primitive unit cell (b) Secondary unit cell (c) Layered unit cell (d) Derived unit cell

A

7 Every point of space lattice has -------- surroundings.

(a) Atoms (b) Element (c) Lattice (d) Identical

D


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8 A cubic crystal system is represented by:

(a) a = b = c, α = β = γ ≠ 90° (b) a = b ≠ c, α = β = γ = 90° (c) a = b = c, α = β = γ = 90° (d) a ≠ b ≠ c, α = β = γ = 90°

C

9 The correct order of the packing density in different types of unit cells is .........

(a) fcc< bcc < sc (b) fcc> bcc > sc (c) fcc< bcc > sc (d) bcc <fcc>sc

B

10 Effective number of atoms per unit cell in BCC is______

(a) 2 (b) 4 (c) 6 (d) 8

A

11 ------------parameter means the dimension of a unit cell of a crystal

(a) Identical (b) Nucleus (c) space (d) Lattice

D

12 Which of the following is a property of amorphous solids?

(a) Sharp melting point (b) Isotropy (c) Long range order (d) Definite heat of fusion

B

13 Co-ordination number of an atom in a crystalline solid is:

(a) Number of particles in the unit cell (b) Number of nearest &equidistant atoms (c) Number of octahedral voids in a unit cell (d) Number of tetrahedral voids in a unit cell

B

14 Atomic packing fraction of a crystal structure is the ratio of:

(a) Volume occupied by effective no. atomsin a unit cell to the total volume of the unit cell (b) Volume occupied by particles to that by voids (c) Total volume of the unit cell to the volume occupied by atoms. (d) Volume occupied by voids to that by particles

A

15 What is the atomic radius of a BCC crystal structure? D


of 44

(a) a/2 (b) a/4 (c) a√2/4 (d) a√3/4

16 What is the atomic packing fraction of FCC structure? (a) 0.54 (b) 0.68 (c) 0.74 (d) 0.96

C

17 The percentage of void space in a simple cubic structure is.......... (a) 74% (b) 68% (c) 32% (d) 48%

D

18

The sharp melting point of crystalline solids is due to ......... (a) a regular arrangement of constituent particles observed over a short distance in the crystal lattice. (b) a regular arrangement of constituent particles observed over a long distance in the crystal lattice. (c) same arrangement of constituent particles in different directions. (d) different arrangement of constituent particles in different directions

B

19 Miller Indices of a given plane are represented by (a) (h k l) (b) <h k l > (c) {{h k l}} (d) [h k l]

A

20 Bragg’s Law of diffraction is expressed as 2dsinθ = ______ (a) (n+1) λ (b) nλ (c) 2nλ ( d) (n-1) λ

B

21 The coordination numbers inBCC, SCand FCC structuresare respectively, (a) 8, 6, 12 (b) 6, 8, 12 (c) 6, 12, 8 (d) 8, 12, 12

A

22 Bragg’s law is related with study of diffraction of___ (a) Electron (b) photons (c) X-rays (d) Gamma rays

C

23 Unit cells for most of the crystals are: (a) spherical (b) elliptical (c) parallelopiped (d) rhombus

C

24 Crystal structure = ______ (a) Space Lattice + Basis (b) Basis + Unit Cell (c) Unit cell+ lattice (d) space lattice + unit cell

A


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25 Identify the plane drawn in figure below:

(a) (110) (b) (111) (c) (101) (d) (100)

B

26 Miller indices of a set of planes with intercepts a, 2a and 3a on x, y, and z axes respectively for cubic crystal are (a) (311) (b) (123) (c) (632) (d) (321)

C

27 Nickel crystallizes in FCC lattice. The edge of the unit cell is 3.52 Å. The atomic weight is 58.72 kg/k mol. Determine the density of the Nickel. Given: Avogadro’s No. = 6.023X 1026 atoms/ k mol.

(a) 7900 kg/m3

(b) 8941.3 kg/m3

(c) 6978 kg/m3

(d) 8200 kg/m3

B

28 The Bragg angle for first order reflection from (111) plane in a crystal is 30o when X-rays of wavelength 1.75 Å is used. Calculate interplanar spacing for the given plane. (a) 1.91 Å (b) 1.56 Å (c) 1.75 Å (d) 1.25 Å

C

29 Aluminium has FCC structure. Its density is 2700 Kg/m3. Calculate its unit cell dimension. Given: Atomic Weight of Aluminium =26.98, Avogadro’s No. = 6.023X 1026 atoms/ k mol.

(a) 4.049 Å (b) 4.86 Å (c) 5.87 Å (d) 4.86 Å

A

30 Sodium metal crystallizes as a body centred cubic lattice with the cell edge 4.29 Å. What is the radius of sodium atom?

(a) 9.312 × 10–8 cm (b) 2.371 × 10–7 cm (c) 3.817 × 10–7 cm (d) 1.857 × 10–8 cm

D


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31 Atomic radius is defined as, ____ of the distance between the centres of two atoms which are in contact with each other. . (a) 1/12 (b) 1/4 (c) 1/6 d) ½

D

32 The fundamental building block of The crystal structure is called as _____.

(a) Unit cell (b) Miller Indices (c) Basis (d) Lattice point

A

33 Which one of the following Bravais lattice is not part of cubic crystal?

(a) Simple cube (b) Body centered Cube (c) Face centered Cube (d) Base centered cube

D

34 The empty space in crystal structure is called as ____.

(a) Planes (b) Density (c) Void space (d) Miller Indices

C

35 Bragg’s law is not useful in ____.

(a) Crystalline solid (b) Polycrystalline solid (c) Amorphous Solid (d) Single Crystalline solid

C

36 Lattice constants of unit cells are represented by ___ . (a) a,b,c (b) ɑ,β,ϒ (c) h,k,l (d) p,q,r

A

37 Bragg’s Law is useful in ______ (a) Determination of crystal structure (b) Calculating interplanar distance (c) Determination of wavelength of X-rays (d) All of these

D

38 Which one is the correct relation between interplanar distance and miller indices? (a) 𝑑 =

√

A


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(b) 𝑎 = √

(c) 𝑎 = ( )

(d) 𝑑 = ( )

39 The volume for FCC unit cell is ____.

(a) a3 (b) 2a3 (c) a2 (d) a4

A

40 Highest the packing fraction of unit cell, ______will be the void space. (a) Maximum (b) Minimum (c) Zero (d) Both b and c

B

41 Distance between the two planes in crystal is called as____. (a) Interatomic distance (b)Miller indices (c) Interplanar distance (d) All of these

C

42 Set of parallel equidistant planes, passing through the lattice points is known as ____. (a) Crystal Structure (b) Miller Indices (c) Unit cell (d) Lattice Planes

D

43 If the periodicity of the pattern extends throughout the crystal then such type of solid is called as _____. (a) Amorphous solid (b) Polycrystalline solid (c) Single Crystalline solid (d) Non-Crystalline solid

C

44 The atomic radius for simple cubic structure is _____. (a) 𝑟 =

(b) 𝑟 =

(c) 𝑟 = √

(d) 𝑟 = √

A

45 Identify the plane (110).

(a)

B


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(b)

(c)

(d) 46 Calculate the longest wavelength that can be analysed

by a rock salt of spacing d= 2.82 Å in the first order? (a) 5.64 Å (b) 1 Å (c) 6.74 Å (d) 0.96 Å

A

47 X-rays of wavelength 1.5 Å incident on NaCl crystal of spacing 2.8 Å. Calculate the highest order of diffraction? (a) 1 (b) 2 (c) 3 (d) 4

C

48 Find the angle at which second order diffraction spectrum will be observed when X-rays of wavelength 1.5 Å strike on a crystal with spacing 2.5 Å. (a) 36.870 (b) 20.180 (c) 2.180 (d) 0.180

A

49 Find the miller indices of a set of planes with intercepts 3a , 2b and ∞ c on X,Y,Z axes respectively for a cubic crystal. (a) (230) (b)(320) (c) (032) (d) (132)

A

50 Lead exhibit FCC structure with side of unit cell is of 4.95 Å. Find the radius of lead atom. (a) 2.15 Å (b) 1.75 Å (c) 4.24 Å ( d) 7.49 Å

B


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UNIT-5 (Optical Fiber)

Question Number


1-1 What is the principle of working of optical fibre?

(a) Frequency modulation (b) Population inversion (c) Total internal reflection (d) Doppler Effect

C

3-2 The critical angle is the angle of incidence at core to cladding boundary at which angle of refraction is_____.

(a) 60o (b) 90o (c)30o (d)45o

B

6-3 The refractive index of core in Graded Index fibre is ________along the axis.

(a) Minimum (b) Maximum (c) Lowest (d) None of the above

B

7-4 In the structure of optical fibre cable, the refractive index of core is always _______the refractive index of cladding.

(a) greater than (b) less than (c) equal to (d) all of above In the structure of optical fibre cable, the refractive index of cladding is always _______the refractive index of core. Ans. (b)

A

2-5 When a ray of light travels from a denser medium to a rarer medium, it bends ______ the normal.

(a) towards (b) away from (c)back (d) All of the above

B

29-6 ______is a thin transparent cylindrical conduit/ wave-guide.

(a) LASER

B


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(b) An optical fibre (c) Light waves (d) None of the above

7 Modes of propagation in optical fibre are the number of possible allowed paths along which light rays can propagate through the fibre______.

(a) out of Phase (b) in phase (c) not in phase (d) All of the above

B

5-8 ______ is responsible for the light to confine it to the core. OR

______ makes the light to be confined to the core.

(a) Core (b) Cladding (c) Sheath (d) All of the above

B

9 Lower order modes travel with ______ speed as compared to that of higher order modes.

(a)higher (b)lower (c) same (d) None of the above

A

5--10 _______ determines the light collecting/ gathering ability of the optical fibre.

(a) Refractive index (b) Critical angle (c)Numerical Aperture (d) Attenuation

C

11 In an optical fibre critical angle of incidence is given by _______ (where, n1- refractive index of core, n2- refractive index of cladding, n0- refractive index of air)

(a) 𝛷c= sin-1(n1/n2) (b) 𝛷c= sin-1(no/n1) (c) 𝛷c= sin(n1/n2) (d) 𝛷c= sin-1(n2/n1)

D

12 A cone enclosing all possible allowed directions so that they will travel by total internal reflection in the optical fibre is known as_______ (a) Acceptance cone (b) Acceptance angle (c) Angle of cone (d) Refraction angle

A


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22-13 _______ of an optical fibre is a graph in between refractive index and the distance from the axis of the fibre. (a) Numerical Aperture (b) Acceptance angle (c) Refractive Index Profile (d) Refraction angle

C

21--14 In liquid level sensor, as liquid touches the loop of optical fibre, intensity at the detector _________.

(a) increases (b) does not change (c) decreases (d) becomes maximum

C

8-15 The largest number of modes of propagation of light rays propagate in _______.

(a) Step index single mode fibre (b) Step index multimode fibre (c) Graded Index Fibre (d) None of the above

B

10-16 Intrinsic absorption is mechanism of _________ OR Intrinsic absorption causes________of signal (a)Attenuation (b) Dispersion (c) both (a) & (b) (d) None of the above

A

17 Smallest core diameter is in______

(a) Graded Index Fibre (GRIN) (b) Multi Mode Step Index Fibre (MMF) (c) Step index single mode fibre (d) All of the above

C

11-18 According to Rayleigh, Intensity of scattered light is inversely proportional to fourth power of _____________.

(a)Frequency (b) Wavelength (c)Time period (d) Momentum

B

12-19 The ratio of the input optical power to the output optical power over length L of an optical fibre is known as_______.

(a)Dispersion (b)Attenuation (c) Geometrical Defect (d) Bandwidth

B


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20 Intermodal dispersion is zero in ______.

(a)Graded Index Fibre (GRIN) (b) Multi Mode Step Index Fibre (MMF) (c) Step index single mode fibre (d) All of the above

C

13-21 ______describes pulse- broadening effect at output end of an fibres. or

Pulse- broadening effect at output end of an fibres is known as_____________.

(a) Absorption (b) Dispersion (c) Numerical Aperture (d) Attenuation

B

33--22 Fibre optic sensors consists of light source coupled with an optical fibre and a _____ held at the receiver end.

(a) LED (b) LASER (c) Light Detector (d) None of the above

C

23 23 In temperature sensor, fibre is coated at end with a thin layer of_____.

(a) Copper (b) Silicon (c) Aluminium (d) Zinc

B

30--24 Speed of _____ order mode is highest in an optical fibre.

(a) Lower (b) Higher (c) Zero (d) None of above

C

25 Which of the following advantages optical fibres have over the conventional conducting wires?

(a) Cheaper (b) Smaller in size (c) No cross talk (d) All of the above

D

14-26 Calculate the numerical aperture of an optical fibre whose core and cladding are made of materials of refractive index 1.6 and 1.5 respectively.

(a) 0.55677 (b) 55.77 (c) 0.2458

A


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(d) 0.647852

Calculate the numerical aperture of an optical fibre whose core and cladding are made of materials of refractive index 1.54 and 1.45 respectively. Ans :--0.5187

15-27 The numerical aperture of an optical is 0.5 and the core refractive index is 1.54. Find the refractive index of cladding.

(a) 1.85 (b) 1.45 (c) 1.65 (d) 1.95 The numerical aperture of an optical fibre is 0.43 and the core refractive index is 1.61. Find the refractive index of cladding.

Ans:1.55

B

25--28 Calculate the angle of acceptance for a given optical fibre if the refractive indices of the core and the cladding are 1.563 and 1.498 respectively.

(a) Acceptance angle = 26.480 (b) Acceptance angle = 86.480 (c) Acceptance angle = 46.480 (d) Acceptance angle = 56.480

Calculate the angle of acceptance for a given optical fibre if the refractive indices of the core and the cladding are 1.6 and 1.5 respectively.

Ans: 18.0590

A

32--29 What is the attenuation in dB/km if 15% of the power fade at the launching end of 0.5 km fibre is lost during the propagation?

(a) 1.81 dB/km (b) 2.81 dB/km (c) 1.41 dB/km (d) 4.81 dB/km What is the attenuation in dB/km if 25% of the power fade at the launching end of 0.5 km fibre is lost during the propagation?

Ans—2.4966 dB/km

C

24-30 In an optical fibre, the core material has refractive index 1.6 and refractive index of clad material is 1.3. What is the value of critical angle?

A


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(a) 54.3 ͦ (b) 55.3 ͦ (c) 56.3 ͦ (d) 58.4 ͦ Practice for: In an optical fibre, the core material has refractive index 1.8 and refractive index of clad material is 1.6. What is the value of critical angle?— Ans. Is 62.62290

17--31 Higher order modes travel with __ lower ____ speed as compared to that of lower order modes. (a)higher (b)lower (c) same (d) None of the above Lower order modes travel with __ higher ____ speed as compared to that of higher order modes.

B

31--32 A maximum incident angle at core with axis for which light can travel by total internal reflection through an optical fiber is known as a) Optical angle b) Total internal reflection angle c) Refraction angle d) acceptance angle

D

33 Which of the following optical fibres are useful for long distance communication? (a) Glass- glass (b) Glass- plastic (c) Plastic-plastic (d) None of these

A

34 If Numerical Aperture (NA) = 0.22 and Δ = 0.012 where Δ is the fractional refractive index change. The refractive indices of the core and cladding of a fibre is ----- respectively. (a) 1.71 and 1.69 (b) 1.42 and 1.40 (c) 2.11 and 1.99 (d) 1.10 and 1.07

B

35 How does the refractive index of core vary in Graded Index Fiber away from the axis of the fiber? (a) Tangentially (b) Radially (c) Horizontally (d) Along the axis of the fiber

B

36 Micro bend losses are caused (a)Due to irregularities in the fibre structure

B


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(b)Due to small bendings in the fibre (c)Due to large bendings in the fibre (d)Due to no bendings in the fibre

37 Commonly used photo detector in the sensor applications is (a)Zener diode (b)Photo diode (c)PN junction diode (d) None of these

B

38 The diameter of core is about

(a) 50-100um (b)100-125um (c)125-150um (d)None of these

A

17-39 Optical fibres are classified on the basis of (a)Material used for Core & Cladding (b)Refractive Index profile (c)No. of modes of propagation (d)All of these

D

40 If the angle of incidence is equal to critical angle then (a)The ray reflects back into the denser medium (b)The ray just travels along the interface of denser & rarer medium (c)The ray refracts into the rarer medium (d)other

B

18-41

Calculate the fibre attenuation when laser of 10-3 W is launched into an optical fibre of length 250 m and the emerging power from other end is 0.5 mW.

(a) 52.28 dB/km (b) 12.04 dB/km (c) 13.04 dB/km (d) 53.29 dB/km

B

42 The angle of incidence for which , the angle of refraction is 90 degree ,when light travels from denser to rare medium is known as __________ (a) Incident angle (b) Apparent angle (c) Critical angle (d) None of these

C

43 Condition for Total Internal Reflection is

(a) Øc >Ø , n2<n1 (b) Ø < Ø0> Ø c , n1<n2 (c)Ø < Øc , n2>n1

D


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(d) Ø > Øc, n1>n2

44 Material dispersion arises due to (a) different wavelengths travel with different speeds through same material (b) different wavelengths travel with same speed through same material (c) Difference in amplitudes of travelling waves (d) None of these

A

26--45 Attenuation is defined as the phenomenon in which the intensity of the light __________as it travels along the optical fibre.

(a) Increases (b) Remains same (c) Decreases (d) None of these

C

27--46 Multimode step index fibre has ___

(a) Large core diameter and large numerical aperture (b) Large core diameter and small numerical aperture

(c)Small core diameter and large numerical aperture

(d) Small core diameter and small numerical aperture

A

47

Numerical aperture & Acceptance angle is constant for (a) GRIN (b) Step Index fibre (c) Both of the above (d) None of these

B

48

FRIC is dependent on (a) Acceptance angle (b) R.I of core (c) R.I. of Cladding (d) Both of these

D

49 Optical fibre carries signals in the form of

a) electricity (b) sound (c) light (d)All of the above

C

50 Inter modal dispersion is generally observed in

(a) Single mode (b) Multi mode (c) Both (A) and (B)

B


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(d) None of these

UNIT-6 (Electron Optics)

Question Number


1 Which part of the following is not a basic part of a CRT? (a) Electron gun (b) Fluorescent screen (c) Horizontal and vertical deflecting system (d) Time base generator

D

2 Bethe's law is related to (a) Law of reflection of light (b) Law of refraction of light (c) Law of refraction of electron (d) Law of refraction of neutron

C

3 The time base circuit of a CRO is used to produce (a) Sinusoidal voltage for the horizontal deflection of electron beam (b) Saw tooth voltage for the vertical deflection of electron beam (c) Sinusoidal voltage for the vertical deflection of electron beam (d) Saw tooth voltage for the horizontal deflection of electron beam

D

4 To select a charged particle of single velocity from a beam of charged particles having different velocities, we need

C


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(a) E > B (b) E < B (c) E = v B (d) E = B

5 The ratio of refractive index of electrostatic field is

(a) 2/1

2

1

V

V

(b)

2

1

V

V

(c) 2/1

1

2

V

V

(d) 2/1V

C

6 Lissajous’s Pattern on CRO screen is obtained when, (a) X input is in internal mode with sinusoidal signal (b) X & Y input are given sinusoidal signals (c) Simultaneous application of sinusoidal signal in mutually perpendicular direction. (d) Both b & c

D

7 A CRO can be used to measure a) A.C. Voltage only b) D.C. Voltage only c) Frequency d) All of the above

D

8 Synchronization is the method of ____________ a) Unlocking the frequency b) Locking A.C. Voltage c) Locking the Frequency d) Unlocking A.C. Voltage

C

9 Pair of Horizontal plates of CRT are placed to control motion of electron beam along _________

(a) Horizontal direction (b) Vertical direction (c) Diagonally (d) None of these

B

10 If the negative voltage of control grid increases, then intensity of electron beam

(a) Increases (b) Same (c) Decreases (d) Different

C

11 In CRT aquadag coating is used to complete the electrical circuit from

(a) cathode to anode

C


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(b) screen to anode (c) screen to cathode (d) all the above

12 The Velocity filter uses

(a) Uniform Magnetic field (b) Electric field (c) Crossed E & B fields (d) None of these

C

13 Bainbridge Mass Spectrograph is used to determine the masses of….. a) Isobar b) Isotopes c) Both d) None of these

B

14 In Electrostatic Lens, the role of the first half of Non-uniform Electric field is (a) To converge the beam (b) To diverge the beam (c) To converge and diverge the beam (d) None of these

A

15 The process of making retrace path invisible is called ________ a) Blanking b) Synchronization c) Focusing d) None of the above

A

16 When an electron beam travels from a region of lower potential to a region of higher potential, its velocity, a) Decreases b) Increases c) Remains constant d) none of above

B

17 Bethe’s Law of electron refraction is expressed as

(a) =

b) =

c) =

d)

=

A

18 A stream of electrons experiences a change in direction of motion when it travels through --------- a) uniform electric field b) non-uniform electric field

B


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c) steady electric field d) constant magnetic field

19 An electron lens can-------- all electrons on the axis. a) converge b) diverge c) split d) deviate

A

20 In Velocity Selector, the electrons will travel undeviated path only if the velocity is …. (a) B/E (b) Root of B/E (c) E/B (d) Root of E/B

C

21 When an electron enters at transverse electric field its path will be (a) Parabolic (b) Circular (c) Elliptical (d) Straight line

A

22 The function of aquadag coating is to

(a) diverge the electron beam (b) Deposit a layer of electrons on screen (c) To complete the electrical circuit from screen to cathode (d) All the above

C

23 An elliptical Lissajou’s pattern on CRO screen means,

(a) signal frequency on x plate is twice to y plate (b) signal frequency on x plate is equal to y plate (c) signal frequency on x plate is half to y plate (d) signal frequency on x plate is unequal to y plate

B

24 In Bainbridge Mass Spectrograph the radius of circular path is directly proportional to

(a) Mass of ions (b) Charge of electron (c) Magnetic field (d)None of the above

A

25 The function of Trigger Circuit

(a) To achieve synchronization (b) To avoid blanking of the screen (c) To focus the electron beam (d) None of the above

A

26 In a Bainbridge mass spectrograph E = 8 x 104 V/m, the magnetic field is common to both is 0.55 Wb/m2. The mass of the neon isotopes are 20 and 22. Calculate the linear separation. (Given: charge q=1.602X10-19C,

B


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1a.m.u. =1.67X10-27 kg.)

(a) 15 mm (b) 11 mm (c) 9 mm (d) 21 mm

27 In Bainbridge mass spectrograph a potential difference of 1000 V is applied between two plates separated by 1 cm and magnetic field B = 1T. The velocity of undeflected positive ions in m/s from the velocity selector is

(a) 107 m/s (b) 104 m/s (c) 105 m/s (d) 102 m/s

C

28 In Bainbridge Mass Spectrograph, singly ionized atom of Ne20 passes into analyzing chamber having a uniform magnetic field B = 0.07 Wb/m2. Determine the radius of the path (v = 103 m/s) Given: charge q =1.602X10-19 C, 1 a.m.u. =1.67X10-27 kg.)

(a) 0.92 mm (b) 1.52 mm (c) 1.92 mm (d) 2.97 mm

D

29 Electrons accelerate by potential difference of 250 V enter the electric field at angle of incidence of 500 and get refracted through an angle of 300. Find the potential of second region.

(a) 586.75V (b) 58.67 V (c) 5.867 V (d) 0.0587 V

A

30 An electron beam passes through a magnetic field of 2x10-3 T and electric field 3.4 x104 V/m, both acting simultaneously at the same point. Path of electron remain unchanged. Calculate electron speed.

(a) 1.7 x107 m/s (b) 1.9 x108 m/s (b) 2 x107 m/s (d) None of these

A

31 Horizontal deflection plates are also called as (a) Y plates (b) X-plates (c)X-Y Plates (d) None of these

B

32 The function of electron gun is to produce _______. (a) Poorly focused B


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beam (b) Sharp electron beam (c) any type of beam (d) Both b and c

33 The synchronization condition is given by ______. (a) T sweep = n Tsignal (b) Tsignal = nT sweep (c) Tsignal = T sweep/ n (d)n/ Tsignal =T sweep

A

34 Is it possible to display the voltage waveform on the CRO screen without time base generator? (a) Possible (b) Not possible (c) May be (d) Both a and c

B

35 Heart of CRO is _____. (a) CRT (b) Trigger circuit (c) Low voltage power supply (d)Vertical Amplifier

A

36 Which part of CRT is used for visual representation of signals ? (a)Electron gun (b)Deflection system (c)Fluorescent Screen (d) Time base generator

C

37 A charged particle moves with velocity (v) in parallel magnetic field (B). Then force acting on the charged particle is ______. (a) Bev (b) eE (c) 0 (d) Bev sinθ

C

38 To get a steady or stable wave pattern on the CRO screen which circuit is used? (a) Delay line (b) Vertical amplifier (c) Trigger circuit (d) Time base circuit

C

39 The intensity of the electron beam is controlled by which part of CRT? (a)Focusing anode (b)X-plate (c)Aquadag coating (d)Control grid

D

40 The Trajectory of an electron under the influence of a uniform magnetic field, when it is injected in the perpendicular direction to the magnetic field is…..

(a)Circular (b) Helix (c) Linear

A


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(d) Parabolic 41 The interior part of CRT screen is coated with which material?

(a)Phosphorus (b) No Coating (c) Zinc Oxide (d) Plastic Coating

A

42 An electric field having the same intensity and same direction at every point in a region is called _____.

(a) Non uniform electric field (b) Homogeneous electric field (c) Uniform electric field (d) Both b and c

D

43 Function of delay line in CRO is to, (a) produce delay in electron reaching screen. (b) produce required delay in Horizontal signal reaching screen (c) produce required delay in Vertical signal reaching screen (d) none of the above

C

44 Electron beam can be focused with the help of ______. (a)Trigger circuit (b) Aquadag coating (c) Control grid (d) Focusing anode

D

45 Lorentz force is (a)Vector sum of electrostatic and magnetic force acting on moving charged particle. (b) Vector sum of gravitational and magnetic force acting on moving charged particle. (c) Magnetic force acting on moving charged particle. (d) Electric force acting on moving charged particle.

A

46 An electron starts from rest and moves freely in an electric field of intensity 1500 V/m. Determine force on electron.( 1.602x 10 -19

(a)2.4 x 10-16 N (b) 3.5 x 10-16 N (c) 3.5 x 1014 N (d) 2.64 x 1014 N

A

47 In Bainbridge mass spectrograph, magnetic field B= 1.0T and ions having speed of 4x 106m/s .What should be the electric field between the plates of velocity selector?

(a)3x 106 m/s (b)4x 105 m/s (c)4x106 m/s (d)2x104 m/s

C


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48 In Bainbridge Mass Spectrograph, the isotopes of masses are 116,117,118,119 and 120 a.m.u. The electric and magnetic fields are E= 20kV/m and B = 0.25 T. Find the spacing between the lines 116 and 120. determine the radius of the path (v = 103 m/s)

(a)2.7 cm (b) 2.7 x 10 -3 m (c)2.7 x 10 -5 m (d) 2.7mm

A

49 Momentum selector in BMS deploys,.

(a) Crossed Electric & Magnetic field (b) Only uniform magnetic field (c) Only electric field (d) Non uniform Electric field

B

50 An electron beam passes through a region of potential 75V into region of potential 100V, making an angle of 450 with direction of electric field. Find the angle through which beam refracts.

(a)37.760

(b) 35.760 (c)1.9 0 (d)22.10

A

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