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Practice Test - 7

Welcome to your AS-7

1. 
The Poynting vector represents:

2. 
The energy density of an electromagnetic wave is proportional to:

3. 
For X-ray with λ = 0.1 nm, what is photon energy in keV? (hc = 1240 eV·nm)

4. 
A photon exerts radiation pressure on a surface. Radiation pressure is related to photon momentum p by:

5. 
For light of wavelength λ, photon momentum magnitude is p = h/λ. The de Broglie wavelength of electron and photon relation is:

6. 
A beam of light contains photons of two wavelengths 400 nm and 800 nm. Which photons carry four times the energy of the other?

7. 
In photoelectric experiment, electrons are emitted even if light intensity is extremely low provided ν > ν0. This proves that:

8. 
Which of the following correctly compares X-rays and microwaves?

9. 
A metal emits electrons when illuminated with 300 nm light; with 600 nm light it does not. What can be inferred about work function?

10. 
For a given metal with φ = 2.0 eV, what is threshold frequency ν0? (h = 6.626×10^−34 J·s)

11. 
The work function for sodium is 2.3 eV. What is threshold wavelength λ0?

12. 
If the intensity of monochromatic light is raised, which of the following increases linearly?

13. 
A photon has energy 4.0 × 10^-19 J. What is its corresponding wavelength?

14. 
Which of following is correct dimensionally for Planck constant h?

15. 
A metal surface has threshold frequency ν0. If incident frequency ν = 1.5 ν0 and stopping potential is V0, what happens to V0 if frequency doubled?

16. 
In the photoelectric effect, why does increasing light intensity NOT increase kinetic energy of emitted electrons?

17. 
The wavelength of a radiation is decreased from 600 nm to 300 nm. What happens to its frequency?

18. 
For blackbody, Stefan–Boltzmann law states total emitted power per unit area ∝ T^4. If temperature doubles, emitted power per unit area becomes:

19. 
Which of these pairs correctly relates wavelength and energy?

20. 
Which formula gives energy of photon in J when wavelength λ in meters is known?

21. 
An electron is struck by a photon and ejected. If photon energy exactly equals φ + K.E., and φ is doubled for same metal, to eject same K.E. you must:

22. 
Which of following gives correct units for wave number?

23. 
In spectroscopy, high wave number corresponds to:

24. 
Which measurement in a photoelectric experiment yields Planck’s constant h?

25. 
A metal has a threshold frequency of 6 × 10^14 Hz. Light of frequency 9 × 10^14 Hz is incident. What is the kinetic energy of the emitted electrons?

26. 
Which radiation has the highest penetrating power?

27. 
The Compton effect shows that:

28. 
Which of these values corresponds to visible spectrum wavelength range?

29. 
A monochromatic light of intensity I hits a metal surface. Doubling intensity will:

30. 
Which experimental observation allowed Einstein to propose photon concept?

31. 
If an electron is ejected with kinetic energy K from a metal when light frequency ν is used, the stopping potential V0 is:

32. 
If threshold wavelength λ0 for a metal is 400 nm, what is its work function φ (in eV)? (Use 1240 eV·nm)

33. 
In Einstein’s photoelectric equation, which term represents threshold condition?

34. 
A photon of wavelength 1240 nm has energy:

35. 
Which of the following expresses relation between energy, frequency and wavelength?

36. 
Which is true for light with very large wave number (in spectroscopy)?

37. 
Which of the following decreases when light enters a denser medium from vacuum?

38. 
Which of these phenomena require considering both wave and particle nature of light?

39. 
If an electron is ejected with maximum kinetic energy 2.0 eV when light of ν = 6×10^14 s^−1 is incident, what is work function φ in eV? (h = 4.136×10^−15 eV·s)

40. 
A monochromatic light gives stopping potential 0.5 V on a certain metal. If wavelength is decreased, stopping potential will:

41. 
If electron binding energy in an atom increases, threshold frequency for photoionization will:

42. 
Which is true for blackbody radiation?

43. 
Which of these is NOT explained by quantum theory?

44. 
Photoelectric effect demonstrates which property of light?

45. 
Which is true about ultraviolet catastrophe and Planck’s solution?