Question

The stopping potential V for photoelectric emission from a metal surface is plotted along Y-axis and frequency v of incident light along X-axis. A straight line is obtained as shown. Planck’s constant is given by

• A. Slope of the line
• B. Product of slope on the line and charge on the electron
• C. Product of intercept along Y-axis and mass of the electron
• D. Product of Slope and mass of electron

Answer 1

Answer: (B)

$K_{\max }=h v-h v_{0} $
$\Rightarrow e V_{0}=h v-h v_{0} $
$\Rightarrow V_{0}=\frac{h}{e} v-\frac{h v_{0}}{e}$
Comparing this equation with $y=m x+c$,
we get slope $m=\frac{h}{e} $
$\Rightarrow h=m \times e$