Light of wavelength $0.6 μ m$ from a sodium lamp falls on a photocell and causes the emission of photoelectrons for which the stopping potential is $0.5 V$ . With light of wavelength $0.4 μ m$ from a mercury vapor lamp, the stopping potential is $1.5 V$ . Then, the work function [in electron volts] of the photocell surface is

Question

Verified by Toppr

Answer 1

Energy of $0.6 μ m$ is $\frac{h c}{0 . 6 * 1 0 ^{- 6}}$ $= 2.05 e V$

stopping potential is $0.5 v$ i.e, $K . E = 0.5 e V$
work function of material = $2.05 - 0.5 e V$
= $1.5 e V$

Answer 2

Energy of

0.6 μ m

is

\frac{h c}{0 . 6 * 1 0 ^{- 6}}

= 2.05 e V

stopping potential is

0.5 v

i.e,

K . E = 0.5 e V

work function of material =

2.05 - 0.5 e V

=

1.5 e V