Question:
Two monochromatic beams A and B of equal intensity I, hit a screen. The number of photons hitting the screen by beam A is twice that by beam B. Then what inference can you make about their frequencies?
Solution:
Let nA be the no.of photons falling per second from beam A and nB be the no.of photons falling per second from beam B.
Given,
No.of photons hitting the screen by A is twice that of B
Therefore, nA = 2nB
Energy from the beam A = hvA
Energy from the beam B = hvB
Intensity = I = nAvA = nBvB
vB = 2vA