Question

The kinetic energy of electrons ejected by using light having frequency equal to threshold frequency $\left({\nu }_0\right)$ is:

• A. $h{v}_0$
• B. almost zero
• C. very large
• D. $h/v_0$

Answer 1

Answer: (B)

almost zero

According to Planck's quantum theory, energy is given by following formula, $h\nu =h{\nu }_o+E_k$, where $E_k$ is maximum kinetic energy of electrons and ${\nu }_o$ is threshold frequency.
When $\nu ={\nu }_o$, $E_k=0$.