Question

When light of wavelength 350 nm is incident on a metal surface, the stopping potential of the photoelectrons is measured to be 0.500 V. What is the work function of this metal? (c = 3.00 × 108 m/s, h = 6.626 × 10-34 J ∙ s, 1 eV = 1.60 × 10-19 J) 3.05 eV 4.12 eV 3.54 eV 0.500 eV

Answer 1

Answer:3.05 eV

Explanation:

Given

wavelength of light $\lambda =350 nm$

Stopping Potential $=0.5 V$

and We know Energy of an incoming light is given by

$E=\frac{hc}{\lambda }$

$E=\frac{6.626\times 10^{-34}\times 3\times 10^8}{350\times 10^{-9}}$

$E=5.68\times 10^{-19} J$

or $E=3.55 eV$

From Einstein Photo Electric Equation

$E=\omega _0+K.E.$

and Stopping Potential is equal to gain in kinetic Energy by ejected Electron

$3.55=\omega _0+0.5$

$\omega _0=3.05 eV$