In a photo-electric cell, a retarding potential of $0.5 V$ is required to block the movement of electrons from the cathode when monochromatic light of wavelength $400 n m$ is incident on its surface. Find the work function of the material of the cathode.

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Solution

Given: $V = 0.5 v o l t$
So, stopping potential $= 0.5 v o l t$
$λ = 400 n m$
we know $E_{n} = e v_{0}$
we also know photo electric equation
$h u = W + E_{n}$
$\frac{h c}{λ} = W + E_{n}$
$\frac{6.6 \times 10^{34} \times 3 \times 10^{8}}{400 \times 10^{- 9}} = W + 0.5 \times 1.6 \times 10^{- 19}$
$W = 4.95 \times 10^{- 19} - 8 \times 10^{- 20}$
$= 4.15 \times 10^{- 19} J$
$W = 2.59 e V$ .

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In a photo-electric cell, a retarding potential of 0.5 V is required to block the movement of electrons from the cathode when monochromatic light of wavelength 400 nm is incident on its surface. Find the work function of the material of the cathode.

Given: V=0.5 voltSo, stopping potential =0.5 voltλ=400 nmwe know En=ev0we also know photo electric equationhu=W+Enhcλ=W+En6.6×1034×3×108400×10−9=W+0.5×1.6×10−19W=4.95×10−19−8×10−20=4.15×10−19JW=2.59 eV.

In a photo-electric cell, a retarding potential of $0.5 V$ is required to block the movement of electrons from the cathode when monochromatic light of wavelength $400 n m$ is incident on its surface. Find the work function of the material of the cathode.