Question

The work function of a metal is $h{v}_0$. Light of frequency v falls on this metal. The photoelectric effect will take place only if

• A. ν ≥ ν₀
• B. ν > 2ν₀
• C. ν < ν₀
• D. ν < ν₀/2

Answer 1

The correct option is A

ν ≥ ν₀

The work function of the metal is $W=h{v}_0$. For photoelectrons to get ejected we will need to throw photons carrying energy greater than the work function W. The light shone has frequency ν.

For photoelectric effect,

$E_{photon}\ge W$

$\Rightarrow h\nu \ge h{\nu }_0$

$\Rightarrow \nu \ge {\nu }_0$.

Therefore, (a) is the correct choice!