Question

In the experiment on photoelectric effect, the graph between $E_{max}$ and $v$ is found to be straight line as shown in figure.

The threshold frequency and Planck's constant according to this graph are

• A. $3.33\times {10}^{18}{s}^{-1},6\times {10}^{-34}Js$
• B. $6\times {10}^{18}{s}^{-1},6\times {10}^{-34}Js$
• C. $2.66\times {10}^{18}{s}^{-1},4\times {10}^{-34}Js$
• D. $4\times {10}^{18}{s}^{-1},3\times {10}^{-34}Js$

Answer 1

The correct option is A $3.33\times {10}^{18}{s}^{-1},6\times {10}^{-34}Js$

$K_{max}=hv-W$
W is the intercept on y axis and $h$ is the slope.
Therefore $h=\frac{2.4\times {10}^{-15}}{4\times {10}^{18}}W=2\times {10}^{-15}J\Rightarrow h{v}_0=2\times {10}^{-15}J{v}_0=3.33\times {10}^{18}Hz$