The threshold wavelength for photoelectric emission from a
material is `5200 Å`. Photoelectrons will be emitted when this material is
illuminated with monochromatic radiation from a
(a) 50 W infrared lamp
(b) 1 W infrared lamp
(c ) 50 W ultraviolet lamp
(d) 1 W ultraviolet lamp
.
A. 50 watt infrared lamp
B. 1 watt infrared lamp
C. 1 watt ultraviolet lamp
D. none of these
