Threshold wavelength for photoelectric emission from a material is 5200, Å . Photo-electrons will b

English

Gujarati

Hindi

11.Dual Nature of Radiation and matter

medium

The threshold wavelength for photoelectric emission from a material is $5200\, \mathring A$. Photo-electrons will be emitted when this material is illuminated with monochromatic radiation from a

A$50$ watt infrared lamp

B$1$ watt ultraviolet lamp

C$50$ watt ultraviolet lamp

DBoth $(b)$ and $(c)$

(IIT-1982)

Solution

(d) In this case, for photoelectric emission the wavelength of incident radiations must be less then $5200{ \mathring A}$. Wavelength of ultraviolet radiations is less then this value $(5200 \, \mathring A)$ but wavelength of infrared radiations is higher than this value.

Standard 12

Physics