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?

  • Google+ icon
  • LinkedIn icon
  • 649 views

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.

Jonathan P. A Level Physics tutor, GCSE Physics tutor, A Level Maths ...

About the author

is an online A Level Physics tutor with MyTutor studying at Durham University

How MyTutor Works

Still stuck? Get one-to-one help from a personally interviewed subject specialist.

95% of our customers rate us

Browse tutors

We use cookies to improve your site experience. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok