Question

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

• A. $\ge$
• B. $\le$
• C. $>$
• D. $<$

Answer 1

The correct option is A $\ge$

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 shown has frequency $\nu$.

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!