Physics Chapter 11 Entry test MCQs
26. In Davisson-Germer experiment, the diffracted electron beam from crystal shows
a. Wave property
b. Particle property
c. Quantum property
d. Light property
27. The electron, accelerated by a potential difference V has de-Broglie wavelength 2. If the electron is accelerated by a p.d 4V, its de-Broglie wavelength will be
a. 4λ
b. 2λ
c. λ/4
d. λ/2
28. A proton and an alpha-particle are accelerated through the same potential difference. The ratio of their de-Broglie wavelengths (λp /λa) is
a. 1
b. 2√2
c. 2
d. 1√2
29. The ratio of momenta of an electron and alpha particle which are accelerated from rest by a potential difference of 100 V is
a. 1
b. √me/mα
c. √2me/mα
d. √me/2mα
30. what is the de Broglie wavelength of a proton whose a linear momentum has a magnitude Of 3.3 x 10-23 kgm / s ?
a. 0.02 nm
b. 0.0002nm
c. 0.2 nm
d. 0.002 nm
31. The velocity of a particle of mass m of de-Broglie wavelengths λ is ———–.
a. 2mλc2
b. 2h/mλ
c. h/mλ
d. mλc2/h
32. If E1E2 and E3 are the respective kinetic energies of an electron, an alpha particle and aproton, each having the same de-Broglie wavelength,
a. E2 > E3 > E1
b. E1 > E2 > E2
c. E4 = E2 = E3
d. E1 > E2 > E2
33. If the K.E of a free electron doubles then its de-Broglie wavelength changes by a factor
a. 1/2
b. 2
c. 1/√2
d. √2
34. The magnitude of de-Broglie wavelength (λ) of ellectrons (e), proton (p), neutron (n), and a particles all have the same energy 1 MeV, in increasing order will follow the sequence.
a. λaλnλpλe
b. λeλpλnλα
c. λaλpλnλe
d. λeλpλnλβ
35. The wavelength of matter waves is independent of:
a. Momentum
b. Mass
c. Charge
d. Velocity
36. A particle of Mass M at rest decays into two masses m1 and m2with non-zero velocities. The ratio of De-Broglie wave lengths of the particle λ1/λ2.
a. √m2/m1
b. m1/m2
c. √m1/m2
d. 1:1
37. The Davisson and Garmer experiment indicate
a. Polarization
b. Interference
c. Refraction
d. Electron diffraction
PAST PAPER MCQS
38. Select the correct relation between wave and particle nature of radiation?
a. E = λc/h
b. E = hc/λ
c. E = hλc
d. E = hc/c
39. Which one of the following has the largest energy content?
a. X-rays
b. y-rays
c. Ultra violet radiations
d. Infrared rays
40. Choose the correct relationship, when E = energy, h =plank’s constant, c- velocity of light, f = frequency, lambda = wavelength:
a. E = hf
b. E = hfc
c. E = nλ/c
d. E = c/λ
41. Which of the following is the best evidence for the wave nature of matter?
a. The spectral radiation form cavity radiation
b. The photoelectric effect
c. The reflection of electrons by crystal
d. The Compton effect
42. The momentum of wave of wavelength 1.32 x 10-9 is:
a. 5 x 10-25 Ns
b. 5 x 10-26 Ns
c. 5 x 10-44 Ns
d. 5 x 10-43 Ns
43. Calculate the frequency of a photon having a momentum of 4.42 x 10-26 Ns:
a. 2 x 1016Hz
b. 2 x 1014Hz
c. 2 x 1018 Hz
d. 5 x 1016Hz
44. The de-broglie wave length of particle of mass ”m” moving with kinetic energy ”E” can be written as?
a. √h/2mE
b. h/2mE
c. h/√2mE
d. √h/2mE
45. The Broglie wave length of an electron travelling with a speed of 1 x 107 m / s equal to, ( h = 6.6 x 10-34Js and me = 9.1 x 10-31 kg ):
a. 7.3 x 108m
b. 7.3 x 1011m
c. 7.3 x 10-13 m
d. 7.3 x 10-11 m
46. A 5-watt LED bulb converts 80% of the power photons of wavelength 660 nm. What is the number of photons emitted from the bulb in one second?
a. 6.6 x 107
b. 5.8 x 1034
c. 1.3 x 1019
d. 7.5 x 1018
47. The value and units of the Plank constant ‘h’ can be expressed as:
a. 6.63 x 10-43Js
b. 6.63 x 10-34 Js-1
c. 3.63 x 10-34 Js
d. 6.63 x 10-34Js
48. Calculate energy of a photon of frequency 3 x 1018Hz (h = 6.63 x 10-34Js)
a. 1.89 x 10-16 J
b. 19.89 x 10-18 J
c. 19.89 x 10-16 J
d. 11.89 x 10-16J
49. The wavelength associated with an electron is of the order of:
a. Radio waves
b. Visible light
c. Infrared
d. X-Rays
50. Which photon carries the most energy?
a. Red
b. Blue
c. Green
d. Violet
51. Photon is made up————quarks
a. Quarks in hadrons
b. Basons
c. Masons
d. No quark
52. If clouds were black body———– what would happen?
a. Reflects back
b. Will receive no light on surface
c. Absorbs light
d. Some light would reach surface
53. By Wein’s constant the wavelength and temperature Are related.
a. Equal
b. Inversely
c. Directly
d. None
54. If wavelength = 500nm of a photon, then its frequency is:
a. 7 x 1014Hz
b. 5 x 1014Hz
c. 8 x 1014Hz
d. 6 x 1014Hz
55. Find E in ev “Photon Wavelength was given 1440n m^”
a. 9.32 eV
b. 0.867 eV
c. 0.932 eV
d. 18.67 eV
56. If velocity Becomes 5 times, what happened to De Broglie Wavelength
a. Decrease by 5 times
b. Increase by 5 times
c. Both
d. None