Question

Q.73



what will be the k.E of ejected electron if incident wavelength is double than the threshold wavelength?

Answer 1

The threshold wavelength (commonly known as threshold frequency) is the wavelength/ frequency of a photon with just sufficient energy to liberate an electron.

Photons have an energy E=hf or E=hc/λ.

As wavelength and frequency are inversely proportional to each other. If incident wavelength is double than threshold wavelength(frequency) then the frequency would be half of the incident wavelength and energy pattern is as same as frequency because energy and frequency are directly proportional to each other.