Question

The threshold wavelength for the photoelectric effect for silver is 262 nm. (a) Determine the work function for silver. (b) What is the maximum kinetic energy of an electron emitted from silver if the incident light has a wavelength of 222 nm

Answer 1

Answer with Explanation:

We are given that

Threshold wavelength,$\lambda_0=262 nm=262\times 10^{-9} m$

$1 nm=10^{-9} m$

a.Work function,$w_0=\frac{hc}{\lambda_0}$

Where $h=6.626\times 10^{-34}$

$c=3\times 10^8 m/s$

Using the formula

$w_0=\frac{6.626\times 10^{-34}\times 3\times 10^8}{262\times 10^{-9}}$

$w_0=7.59\times 10^{-19} J$

b.Wavelength,$\lambda=222nm=222\times 10^{-9} m$

$K.E=\frac{hc}{\lambda}-7.59\times 10^{-19}$

$K.E=\frac{6.626\times 10^{-34}\times 3\times 10^8}{222\times 10^{-9}}-7.59\times 10^{-19}$

$K.E=8.95\times 10^{-19}-7.59\times 10^{-19}=1.36\times 10^{-19} J$

Hence, the maximum kinetic energy of an electron emitted=$1.36\times 10^{-19} J$