Question

A photon is indicient having frequency $1\times {10}^{14}{sec}^{-1}$ threshold frequency of metal is $5\times {10}^{13}{sec}^{-1}$. Find the kinetic energy of the ejected electron?

• A. $3.3\times {10}^{-21}J$
• B. $6.6\times {10}^{-21}J$
• C. $3.3\times {10}^{-20}J$
• D. $6.6\times {10}^{-20}J$

Answer 1

The correct option is C $3.3\times {10}^{-20}J$

We have, $h\nu =h{\nu }_0+KE$

$\Rightarrow KE=h(\nu -{\nu }_0)$

From the given values of respective frequencies and the value of Planck's constant, we have,

$KE=3.313\times {10}^{-20}$