Light of energy 5eV falls on a metal of work function 3eV and electrons are...

Physics

JAMB 2000

Light of energy 5eV falls on a metal of work function 3eV and electrons are liberated. The stopping potential is

A. 1.7V
B. 2.0V
C. 8.0V
D. 15.0V

WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now

Your School's Whatsapp Group - Join Us now

Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts

Correct Answer: Option B

Explanation

For a photoemitted electron,
eV = K.E.max, where V = stopping potential and K.E. = maximum kinetic energy of the photo emitted electron given by K.E. = Energy of incident rad - Work function
= 5ev - 3ev = 2ev
∴ eV = 2eV
V = 2eV/e = 2V
∴ Stopping Potential = 2.0V

There is an explanation video available below.

Previous Next

Go back to Phy classroom

Report an Error Ask A Question Download App