Question

Photoelectric emission occurs only when the incident light has more than a certain minimum

• A. power
• B. wavelength
• C. intensity
• D. frequency

Answer 1

Answer: (D)

According to Einstein's photoelectric equation
$K_{\max }=hv-h{v}_0$
Since $K_{\max }$ is positive, the photoelectric emission occurs only if
$hv>{\text{ hv }}_0\text{ or }v>v_0$
The photoelectric emission occurs only when the incident light has more than a certain minimum frequency. This minimum frequency is called threshold frequency.