Physics

Problem

In a historical experiment to determine Planck's constant, a metal surface was irradiated with light of different wavelengths. The emitted photoelectron energies were measured by applying a stopping potential. The relevant data for the wavelength (

\lambda

) of incident light and the corresponding stopping potential (

V_0

) are given below:

$\lambda$ ( $\mu\text{m}$ )	$V_0$ (Volt)
0.3	2.0
0.4	1.0
0.5	0.4

Given that

c = 3 \times 10^8 \text{ m s}^{-1}

and

e = 1.6 \times 10^{-19} \text{ C}

, Planck's constant (in units of

\text{J s}

) found from such an experiment is<br>&emsp;(a)

6.0 \times 10^{-34}

<br>&emsp;(b)

6.4 \times 10^{-34}

<br>&emsp;(c)

6.6 \times 10^{-34}

<br>&emsp;(d)

6.8 \times 10^{-34}

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