Question

The threshold frequency of potassium is $3\times {10}^{14}Hz$. Its work function is-

• A. $1.0\times {10}^{-19}J$
• B. $2\times {10}^{-19}J$
• C. $4\times {10}^{-19}J$
• D. $0.5\times {10}^{-19}J$

Answer 1

The correct option is B $2\times {10}^{-19}J$

Work function will be $\varphi =h{\nu }_0=6.62\times {10}^{-34}Js\times 3\times {10}^{14Hz}=19.86\times {10}^{-20}J$ which is nearly $2\times {10}^{-19}J$

Option B is correct.