Threshold wavelength for lithium metal is 6250 Å. For photo emission, the wavelength of the incidennt light must be

Options

A. exactly equal to 6250 Å
B. more than 6250 Å
C. equal to or more than 6250 Å
D. equal to or less than 6250 Å

Answer

D

Explanation

Threshold wavelength for lithium metal is 6250 Å. For photoemission, the wavelength of the incident light must be equal to or less than 6250 Å.