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Class 12 Physics (Part Ii) Chapter 11 Dual Nature Of Radiation And Matter Quiz 3 (25 MCQs)

Quiz Instructions

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1. If 'h' is plank's constant, the momentum of a photon of wavelength 0.01 A$^{0}$

Correct Answer: D) 10$^{12}$ h.

2. A monochromatic source of light is placed at a distance d from a metal surface. Photoelectrons are ejected at a raten and with maximum KE = E. If the source is brought to a distance d/2, the rate and maximum KE of photoelectronsbecome, respectively,

Correct Answer: C) 4n and E.

3. Wave theory of light predicted that ..... which is false

Correct Answer: A) "As in intensity increases, kinetic energy of the electron increase s".

4. Explain the concept of wave-particle duality.

Correct Answer: C) Particles can exhibit both wave-like and particle-like properties.

5. In various experiments on photo electricity the stopping potential for a given frequency of the incident light

Correct Answer: C) Is incident of the radiation intensity.

6. Who Proved that electron was wave?

Correct Answer: B) Davisson and Germer.

7. Photoelectric effect was first discovered by

Correct Answer: C) Hertz.

8. A material particle with a rest mass mo is moving with speed of light c. The de-Broglie wavelength associated is given by:

Correct Answer: A) Mac.

9. An electron is accelerated through a potential difference of 1000 V. The velocity acquired by the electron is

Correct Answer: D) 1.88 x 10 $^{7}$ m s$^{-1}$.

10. Which is De-Broglie Wavelength Formula for Elementary particles?

Correct Answer: C) $\lambda=\frac{h}{p}$.

11. Work function of a metal is the

Correct Answer: B) Minimum energy required by an electron to escape from the metal surface.

12. As the intensity of incident light increases, the

Correct Answer: C) Photoelectric current increases.

13. When photon of energy 'hv' falls on an aluminium plate (work function E$_{0}$ ), photo electrons of maximum kinetic energy 'K' are ejected . If frequency of radiation is doubled, the maximum kinetic energy of the ejected photo electrons will be

Correct Answer: D) K+hv.

14. The dimensional formula for Plancks constant is

Correct Answer: A) $ML^2T^{-1}$.

15. Alpha, beta & gamma rays carry same momentum, which has the longest wavelength

Correct Answer: D) All have same wavelength.

16. Photoelectric effect is

Correct Answer: D) Emission of electrons by metals when illuminated by light of suitable frequency.

17. The energy spent in releasing the photoelectrons from a metal surface is called .....

Correct Answer: C) Work function.

18. Thomson's cathode-ray tube experiment demonstrated that

Correct Answer: A) Cathode rays are streams of negatively charged ions.

19. In Which case is electron emission form a metal not known?

Correct Answer: A) Heating the metal sufficiently.

20. The work functions of sodium and copper are respectively 2.0 eV and 4.0 eV. The maximum velocity of an electron emitted by light of wavelength 4000A incident on the surface of a metal is:

Correct Answer: A) Sodium.

21. The minimum amount of energy required to liberate a photo electron from the metal surface is called as .....

Correct Answer: B) Work function.

22. At the stopping potential, photoelectric current is .....

Correct Answer: C) Zero.

23. Photoelectric effect phenomenon was discovered by:

Correct Answer: C) Hertz.

24. In photoelectric effect

Correct Answer: C) Light energy is converted into electric energy.

25. The specific charge of proton is 9.6 x 10$^{7}$ C kg$^{-1}$. What is the specific charge of alpha particle

Correct Answer: C) 4.8 x 10$^{7}$ C kg$^{-1}$.

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