Question

When ultraviolet radiation is incident on a surface, no photoelectrons are emitted. If a second beam causes emission of photoelectrons, it may consist of :

• A. Radio waves
• B. Infrared rays
• C. Visible light rays
• D. X-rays

Answer 1

Answer: (D)

X-rays

Order of frequency-
x-rays $>$ ultraviolet rays $>$ visible light rays $>$ infrared rays $>$ radio waves
So, it ultraviolet rays were not able to emit electrons. So, visible light rays, infrared rays and radio waves cannot emit electrons due to less energy of these rays. But x-rays have energy greater than ultraviolet rays so, it may emit photons.
Energy $=h\nu$

where, $\nu$ is frequency of incident light.