Question

The work function of cesium is 2.14 eV. The threshold frequency of caesium is:

• A. $5.16\times {10}^{19}Hz$
• B. $5.16\times {10}^{16}Hz$
• C. $5.16\times {10}^{18}Hz$
• D. $5.16\times {10}^{14}Hz$

Answer 1

Answer: (D)

$5.16\times {10}^{14}Hz$

Here, ${\varphi }_0=2.14eV$

${\upsilon }_0=\frac{{\varphi }_0}{h}=\frac{2.14\times 1.6\times {10}^{-19}}{6.63\times {10}^{-34}}=5.16\times {10}^{14}Hz$