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

1. Use the situation below.

What is the strongest reason for using two different energy routes?

2. A clean metal surface is exposed to two radiations of the same intensity. Radiation has frequency below , while radiation has frequency above . The expected result is

3. Read the situation below and answer the question.

The correct interpretation is

4. Classical wave theory expected a low-intensity beam to produce a delayed photoelectric emission because

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

6. In a Davisson-Germer type setup, a detector peak shifts to a smaller Bragg angle when the accelerating voltage is increased. The shift is consistent with

7. A claim about the - graph says, “The vertical intercept is positive because stopping potential is always positive.” The best response is that

8. Consider the following statements about the experimental laws of photoelectric emission.
Statement I: For , photoelectric current increases with intensity.
Statement II: Maximum kinetic energy depends on frequency and not on intensity.
Statement III: Photoelectric emission has a long unavoidable time lag at very low intensity.

9. For a metal of work function , radiation of wavelength has photon energy . What maximum kinetic energy can the fastest photoelectrons have?

10. The quantum idea of radiation says that electromagnetic radiation exchanges energy with matter in

11. A claim says, “Since a photon has zero rest mass, it cannot have momentum.” The best correction is that a photon

12. A photoelectric-current table is shown below.

The mismatched row is

13. If a photoelectric experiment gives a stopping potential of , the maximum kinetic energy of photoelectrons in is

14. A particle of mass has kinetic energy and is moving non-relativistically. Its de Broglie wavelength may be written as

15. A stopping potential is measured for photoelectrons. Taking and , the maximum speed is closest to

16. In Einstein’s photoelectric equation, the incident photon energy is divided into

17. Assertion: Saturation current in the photoelectric effect depends on the intensity of incident radiation when the frequency is above threshold.
Reason: At saturation, the current is limited by the number of photoelectrons emitted per second.

18. A graph-reading note claims, “The - graph and the - graph have the same slope because both come from Einstein’s equation.” The note should be corrected because

19. When a photon falls on a metal surface of work function , the photoelectric response is

20. A - graph for a metal cuts the frequency axis at . This intercept represents

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

22. A detector in an electron-diffraction experiment records intensity peaks instead of a uniform spread. The peaks show that the electron beam

23. The condition in electron diffraction predicts strong peaks only at certain angles because

24. The work function of a metal is . If , the threshold frequency is

25. An electron beam used for diffraction has de Broglie wavelength . Using , the electron momentum is closest to

26. In a photoelectric experiment, a graph of against for metal is parallel to that for metal . Metal has a larger threshold frequency. For the same above-threshold incident frequency, metal gives

27. A stopping-potential graph has vertical intercept when is plotted against . The work function of the metal is

28. Two metals give straight - graphs. The two lines are parallel, but the line for metal cuts the frequency axis at a larger frequency than metal . The correct conclusion is that

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

30. Matter-wave behaviour is usually noticed for microscopic particles rather than ordinary large bodies because

31. For a surface whose threshold frequency is , with , the work function is closest to

32. Match the component of Lenard’s photoelectric experiment with its role.

The correct matching is

33. For electrons diffracted by crystal planes, the first-order condition is . If and the observed first-order Bragg angle is , the electron wavelength is

34. A unit check for the de Broglie relation should give

35. A particle of mass and charge is accelerated from rest through potential . Another particle has mass and charge , and is accelerated through the same . Their de Broglie wavelengths satisfy

36. For the same metal and same above-threshold frequency, the intensity is changed from to . If the initial saturation current is , the new saturation current is expected to be

37. A photoelectric current is recorded in a circuit connected to an illuminated metal emitter and a collector. The current mainly indicates that

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

39. Which quantity represents the energy gained by a charge when it moves through a potential difference ?

40. A claim says, “Matter waves are electromagnetic waves because every wave must be electromagnetic.” The better statement is that matter waves are

41. The vertical intercept of a - graph, if the straight line is extended to , is

42. The straight-line equation for stopping potential as a function of frequency is

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

44. A photoemissive surface receives above-threshold photons per second. The quantum efficiency is , and all emitted electrons are collected. The photoelectric current is

45. A photoelectric tube is operated with . At , the current just becomes zero. At large positive , the current becomes . The maximum kinetic energy and collected electron rate at saturation are respectively

46. For fixed intensity and fixed frequency above threshold, reducing the collector potential from a positive value to a retarding negative value mainly changes

47. Once photoelectric current is reduced to zero by a stopping potential , increasing the incident light intensity without changing frequency ideally makes the stopping potential

48. In the Hertz observation related to photoelectric emission, ultraviolet radiation helped a spark occur more easily between metal electrodes. A suitable interpretation is that ultraviolet radiation

49. Use the arrangement described below.

Increasing the accelerating potential mainly

50. At fixed above-threshold frequency, increasing the intensity of radiation on a metal surface mainly increases