• CH.PHYSICS

Important questions class 12 physics Dual Nature of Radiation and Matter Waves

Updated: May 5, 2020

Dual Nature of Radiation and Matter

[1 Mark Questions]

1. Define the intensity of radiation on the basis of the photon picture of light. Write its SI unit.

2. The graph shows the variation of stopping potential with the frequency of incident radiation for two photosensitive metals A and B. Which one of the two has a higher value of work-function? Justify your answer.

3. In the photoelectric effect, why should the photoelectric current increases as the intensity of the monochromatic radiation incident on a photosensitive surface be increased? Explain.

4. The given graph shows the variation of photoelectric current (I) versus applied voltage (V) for two different photosensitive materials and for two different intensities of the incident radiation. Identify pairs of curves that correspond to different materials but same intensity radiation.

5. Show on a plot the nature of variation of photoelectric current with the intensity of radiation incident on a photosensitive surface.

6. Define the term stopping potential in relation to the photoelectric effect.

7. Show the variation of photocurrent with collector plate potential for different frequencies but the same intensity of incident radiation.

8. Show the variation of photocurrent with collector plate potential for different intensities but the same frequency of incident radiation.

9. The stopping potential in an experiment on the photoelectric effect is 1.5 V. What is the maximum kinetic energy of the photoelectrons emitted?

10. The maximum kinetic energy of a photoelectron is 3 eV. What is its stopping potential?

11. The stopping potential in an experiment on photoelectric effect is 2 V.What is the maximum kinetic energy of the photoelectrons emitted?

12. The figure shows a plot of three curves a, b, c showing the variation of photocurrent vs. collector plate potential for three different intensitiesI1, I2 and I3 having frequencies υ1, υ2 and υ3 respectively incident on photosensitive surface.

Point out the two curves for which the incident radiations have the same frequency but different intensities.

13. Write the expression for the de-Broglie wavelength associated with a charged particle having charge q and mass m, when it is accelerated by a potential difference.

14. State