Dual Nature of Radiation and Matter Mock Test – Class 12 Physics

1. For work function , radiation of wavelength falls on a metal. Using , the stopping potential is closest to

2. Two particles have the same kinetic energy , but particle has mass and particle has mass . Their non-relativistic de Broglie wavelengths satisfy

3. A table comparing the two wavelength determinations in the Davisson-Germer experiment is shown below.

The row that should be rejected is

4. In a straight-line graph of versus for a metal, the slope is . Taking , the value of obtained from the graph is closest to

5. A non-relativistic electron has de Broglie wavelength . If its kinetic energy is increased four times, its new wavelength is

6. For fixed frequency above threshold, the graph between saturation current and light intensity is expected to be

7. In electron diffraction, clear diffraction maxima are expected when the electron de Broglie wavelength is

8. The table below compares accelerated particles starting from rest through the same potential .

The table is best justified by

9. Which observation is the clearest evidence for the wave nature of matter?

10. Read the observation below and answer the question.

What does this observation mainly indicate?

11. With the same metal, the incident frequency is increased while intensity is adjusted so that the saturation current remains unchanged. The stopping potential

12. The work function of a metal is . Radiation with photon energy , , and is tried one by one. Which outcome is expected?

13. A photosensitive metal surface is illuminated by radiation whose frequency is just above the threshold frequency. The emitted electrons are called photoelectrons because

14. From a photoelectric surface of work function , light ejects fastest electrons that are then treated using de Broglie wavelength. Taking , , , and , the de Broglie wavelength of the fastest photoelectrons is closest to

15. Increasing the accelerating potential in a Davisson-Germer experiment mainly changes the diffraction condition because it changes the electrons'

16. For a surface with , radiation of wavelength is made very intense. The expected photoelectric response is

17. Assertion: Photoelectric emission starts nearly instantaneously when suitable radiation falls on a metal surface.
Reason: In the photon picture, a single photon can transfer its energy as a whole to one electron.

18. Blue light causes photoemission from a metal, but red light does not. A possible threshold wavelength for the metal is one that lies

19. An electron microscope can have better resolving power than an ordinary optical microscope mainly because accelerated electrons can have

20. An electron beam has de Broglie wavelength . Using , the accelerating potential is closest to

21. When the collector plate is made negative with respect to the emitting plate in a photoelectric tube, it is called a retarding condition because

22. For one metal, is plotted against .

The work function of the metal is

23. Assertion: Stopping potential depends on the maximum kinetic energy of photoelectrons.
Reason: At stopping potential, the retarding electric work equals of the fastest photoelectrons.

24. For an electron of de Broglie wavelength , using , the accelerating voltage is about . What is the kinetic energy of the electron in ?

25. For a metal with threshold frequency , the work function is

26. When the collector plate is made negative with respect to the emitter, the photoelectric current decreases because

27. For photon energy plotted against frequency , consider this graph.

The slope of the graph represents

28. A photon has wavelength . An electron also has de Broglie wavelength . The photon energy is , while the electron kinetic energy is much smaller. The main reason is that

29. A claim states, “Stopping potential measures how many photoelectrons are emitted per second.” The better correction is that stopping potential measures

30. The same radiation is incident on two clean metal surfaces. Metal emits photoelectrons, but metal does not. A reasonable conclusion is that

31. When a photon is absorbed by a surface electron in a metal of work function , the simplest photoelectric energy balance gives maximum kinetic energy

32. A sensor uses a photosensitive emitter of work function . It is illuminated separately by photons of energies , , and . The current can appear for

33. A particle has momentum . Using , its de Broglie wavelength is

34. In an electron diffraction experiment, first-order constructive scattering occurs from planes separated by at Bragg angle . Using , the accelerating potential is closest to

35. Read the comparison below.

What is the expected photoelectric response?

36. Threshold wavelength is called the maximum wavelength for photoelectric emission because

37. A claim says, “Increasing the frequency of light always increases photoelectric current.” A better statement is that increasing frequency above threshold certainly tends to increase

38. For a threshold wavelength of , light of wavelength falls on the metal. Using , the maximum kinetic energy is closest to

39. The maximum speed of photoelectrons from a metal is . Taking and , the stopping potential is closest to

40. Assertion: External energy is needed for electron emission from a metal surface.
Reason: Electrons at the metal surface are bound and must overcome a minimum escape-energy requirement.

41. The de Broglie wavelength of a particle of momentum is

42. The following graph description is given.

The correct comparison is

43. The same photoelectric surface is illuminated first by radiation of frequency and then by radiation of frequency . If , the increase in stopping potential is closest to

44. In a vacuum setup, a metal plate is subjected to three actions.

Which assessment of the record is suitable?

45. A photoelectric calculation gives after substituting values into . The correct physical interpretation is

46. A radiation packet has energy . Express this energy in , using .

47. A student uses to find the kinetic energy of an electron from its de Broglie wavelength. The error is that this formula gives

48. For a metal, the stopping potential is at frequency and at frequency . The slope of the - graph is

49. A clean metal plate is illuminated by radiation of frequency below its threshold frequency. Increasing the exposure time alone is expected to

50. A crystal has plane spacing . An electron beam of wavelength gives first-order constructive scattering. The Bragg angle is