JEE Main202329 Jan 2023Morning ShiftPhysicsDual Nature of MatterActual
The threshold wavelength for photoelectric emission from a material is 5500 A ∘ . Photoelectrons will be emitted, when this material is illuminated with monochromatic radiation from a A. 75 W infra-red lamp B. 10 W infra-red lamp C. 75 W ultra-violet lamp D. 10 W ultra-violet lamp Choose the correct answer from the options given below :
Options
- AB and C only
- BA and D only
- CC only
- DC and D only
Correct answer
D. C and D only
Step-by-step solution
Given here, threshold wavelength λ th = 5500   Å = 550   nm For photoelectric emission, the wavelength of the light should be less than 550   nm . Wavelength of infrared radiation extends from 700   nm - 1   mm and that of ultraviolet radiation is 100 - 400   nm . Since, UV light has less wavelength than 550   nm , so only UV would be able to emit photoelectrons.