question_answer

The threshold frequency for a metallic surface corresponds to an energy of 6.2 eV and the stopping potential for a radiation incident on this surface is 5V. The incident radiation lies in [AIEEE 2006]

A) ultraviolet region

B) infrared region

C) visible region

D) X-ray region

Correct Answer: A

Solution :

[a] The threshold energy,and the stopping potential

From Einstein's photoelectric equation,

where,is the wavelength.

Which belongs to ultraviolet region.