Question

The threshold wavelength for photoelectric emission from a material is $5500 \mathring{A}$. 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:

• A. C only
• B. B and Conly
• C. C and D only
• D. A and D only

Answer 1

Answer: (C)

$ \lambda < 5500 \mathring A $ for photoelectric emission
$\lambda_{ uv } < 5500 \mathring A$