Question

define threshold frequency in photoelectric effect and describe the failure of wave theory to explain the existence of a threshold frequency for a photosensitive material​

Answer 1

HELLO!

Threshold Frequency is the minimum frequency below which no photo emission takes place. This means that, if beams of frequency below the threshold frequency is incident on the surface of a metal, no photoelectron will be ejected from the surface.

This uplifts the Particle nature of light and undermines the Wave nature. Because, the ejection of electrons depend on frequency, not on the intensity of light incident. Suppose you keep on increasing the number of beams (intensity) of incident light, keeping their frequency below the threshold frequency. This won't result in photoemission. So, wave theory fails.

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