Question

Assertion : Photoelectric effect demonstrates the wave nature of light.

Reason : The number of photoelectrons is directly proportional to the frequency of light.

A. Both assertion and reason are true and the reason is the correct explanation of the assertion.
B. Both assertion and reason are true but reason is not the correct explanation of the assertion.
C. Assertion is true but reason is false.
D. Assertion and reason both are false.
E. Assertion is false but reason is true.

Answer 1

The assertion is false because the photoelectric effect is a demonstration of the particle nature of light, not the wave nature. It occurs when photons of sufficient energy strike a metal's surface and eject electrons.

Step-by-step explanation:

The assertion that the photoelectric effect demonstrates the wave nature of light is false. The photoelectric effect is actually a classic demonstration of the particle nature of light. According to Einstein's explanation, the photoelectric effect occurs when photons with sufficient energy strike the surface of a metal, transferring their energy to electrons and causing them to be ejected from the material.

For example, increasing the brightness of the incoming light, which is related to the number of photons, increases the number of ejected electrons, not the kinetic energy of each electron. This indicates that individual particles of light ('photons') are interacting with electrons. Moreover, it is the frequency of the light (which is related to the energy of each photon) that affects the kinetic energy of the ejected electrons, further illustrating the particle aspect of light.