Question

The binding energy of electron in a metal is $250kJmol{e}^{-1}$. The threshold frequency of metal is

• A. 6 x 10^-12 s^-1
• B. 6 x 10^-14 s^-1
• C. 6 x 10^-10 s^-1
• D. 6 x 10¹² s^-1

Answer 1

The correct option is B

6 x 10^-14 s^-1

$6.625\times {10}^{-34}\times 6\times {10}^{23}\times v=25.\times {10}^3$

$v=\frac{250\times {10}^3}{6.625\times {10}^{-34}\times 6\times {10}^{23}}$

= $6.3\times {10}^{14}se{c}^{-1}$