Dual Nature Of Light Question 238
Question: The threshold wavelength for photoelectric emission from a material is 5200 Å. Photo-electrons will be emitted when this material is illuminated with monochromatic radiation from a [IIT JEE 1982; MP PMT 1992; MP PET 1999; UPSEAT 2001; KCET 2004; J & K CET 2004; BHU 2004]
Options:
A) 50 watt infrared lamp
B) 1 watt infrared lamp
C) 50 watt ultraviolet lamp
D) 1 watt ultraviolet lamp
E) (e) Both (c) and (d)
Show Answer
Answer:
Correct Answer: E
Solution:
(e) In this case, for photoelectric emission the wavelength of incident radiations must be less then $ 5200{\AA} $ . Wavelength of ultraviolet radiations is less then this value (5200 Å) but wavelength of infrared radiations is higher than this value.
BETA
