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. $v\ge v_0$
• B. $v>2v_0$
• C. $v<v_0$
• D. $v<\frac{v_0}{2}$

Answer 1

The correct option is A

$v\ge v_0$

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!