Question

A graph regarding photoelectric effect is shown between the maximum kinetic energy of electrons and the frequency of the incident light. On the basis of the data as shown in the graph, calculate the work function.

• A. 4eV
• B. 2eV
• C. 4.2eV
• D. 2.5eV

Answer 1

Answer: (A)

From the graph, threshold frequency $v_0=10\times {10}^{14}Hz$
$h=\frac{\Delta k_{\max }}{\Delta v}=\frac{8\times 16\times {10}^{-19}}{20\times {10}^{14}}=6.4\times {10}^{-34}J$
Thus, work function,
$W=h{v}_0=6.4\times {10}^{-34}\times 10\times {10}^{14}$
$=4\times 1.6\times {10}^{-19}=4eV$