Question

The threshold wavelength for photoelectric emission from a material is $5200A^0$.Photoelectrons will be emitted when this material is illuminated with monochromatic radiation from a

• A. $50$ watt infrared lamp
• B. $1$ watt infrared lamp
• C. $50$ watt ultraviolet lamp
• D. $1$ watt ultraviolet lamp

Answer 1

Answer: (C), (D)

The correct options are
C $50$ watt ultraviolet lamp
D $1$ watt ultraviolet lamp

${\lambda }_0=5200\dot{A}$
we know that ${\lambda }_{UV}<{\lambda }_0<\lambda$ Infrared
$E_{UV}>E_0>E_{infrared}$
photoelectron emission does not depend on Intensity of light falling on it.

So, the answers are option (C) & (D).