When red light is shone on a metal, regardless of the intensity of this light, no current will flow. However if blue light is shone on this metal a current will flow. Why does this occur?

This problem can be solved by first considering the energy of a photon e = hf. ​A photon of red light lacks the sufficient energy to free an electron. However a photon of blue light has a higher frequency and thus has a higher energy. This allows for a photon of blue light to free an electron and thus allow for a current to flow when a large number of photons are sent towards the metal.

JP
Answered by Jonathan P. Physics tutor

5442 Views

See similar Physics A Level tutors

Related Physics A Level answers

All answers ▸

How does stimulated emission work?


Derive Keplers 3rd law


Explain the difference between the direction of the conventional current and the direction of electron flow.


Why do atoms larger than iron release energy when they undergo fission?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences