Question

The photocurrent of a photocell is cut off by a retarding potential (stopping potential) of 2.92 V for radiation of wavelength 250 nm. What is the work function of the material?​

Answer 1

$\sf{\pink{→Stopping\: Potential\: (V) = 2.92}}$

$\sf{\pink{→Wavelength (λ) = 250nm}}$

$\sf\green{Energy (E) = \dfrac{1240}{λ} = \dfrac{1240}{250} = 4.96}$

$\sf{\underline{\underline{For\: Stopping\: Potential}}}$

$\sf\orange{K.E = ev = 2.92ev}$

$\sf{\underline{\underline{We\:Know}}}$

$\sf\pink{\fbox{E = Φ + K.E}}$

$\sf\orange{Φ = E - K.E}$

$\sf\orange{Φ = 4.96 - 2.92 = 2.04 \:ev}$

$\sf{Hence,\: Work\: function\: is\: 2.04 \:ev}$