Question

Work function of a metal is 2.51 eV. Its threshold frequency is

• A. $5.9\times {10}^{14}Cycle/sec$.
• B. $6.5\times {10}^{14}Cycle/sec$.
• C. $9.4\times {10}^{14}Cycle/sec$.
• D. $6.8\times {10}^{14}Cycle/sec$.

Answer 1

The correct option is D $6.8\times {10}^{14}Cycle/sec$.

$W_0=h{v}_0\Rightarrow v_0=\frac{W_0}{h}=\frac{2.51\times 1.6\times {10}^{-19}}{6.6\times {10}^{-34}}$
$=6.8\times {10}^{14}Cycle/sec$.