Describe the photoelectric effect and what it tells us about the properties of light .

The photoelectric effect describes the process by which surface electrons are emitted from a metal when light is shined on it. This occurs because the electrons are able to absorb the electromagnetic energy and escape the surface of the metal.

During the photoelectric effect we observe that electrons will not be emitted from the surface of the metal if the light intensity is increased unless the incident light is above a certain frequency known as the threshold frequency. Above this frequency, increasing the intensity of the light increases the number of electrons emitted.  This tells us that light at a higher intensity must contain more quanta of energy, known as photons. These photons collide with the electrons and excite them out of the metal's surface.

Increasing the frequency of the light above the threshold frequency increases the maximum kinetic energy of the electrons released, proving that at a higher frequency each photon has more energy (Energy = Planck's constant * Frequency). Below the threshold frequency, the photons don't have enough energy to excite the electrons off the surface of the metal. This effect therefore illustrates light behaving as a particle, because if it was a wave, increasing the intensity of the light would result in electron emission, but it does not. 

Lorenzo C. GCSE Biology tutor, A Level Biology tutor, GCSE Chemistry ...

1 year ago

Answered by Lorenzo, an A Level Physics tutor with MyTutor

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


£20 /hr

Liam M.

Degree: Mathematics (Bachelors) - St. Andrews University

Subjects offered: Physics, Maths


“Hi! I am a 3rd year at the University of St Andrews studying Mathematics. I have 2 years experience tutoring students one-to-one for Scottish National 5 and Higher Mathematics as well as Higher Physics. These were always subjects I en...”

£20 /hr

Eleanor S.

Degree: Physics (Masters) - Durham University

Subjects offered: Physics, Maths+ 2 more

Further Mathematics

“About Me: Hi, I'm Elle! Science, maths and languages have been my favourite subjects from a young age and studying them in further detail only made me love them more. I am soon to go into my second year of a physics degree at Durham ...”

£20 /hr

Liberty A.

Degree: Mathematics (Bachelors) - Durham University

Subjects offered: Physics, Maths+ 1 more

Further Mathematics

“About Me Hi I'm Libby, I am in my first year studying Mathematics at Durham University and live in Buckinghamshire. I believe Mathematics and Pysics are fantastic subjects and I enjoy tutoring as I am able to share my passion and help...”

MyTutor guarantee

About the author

£36 /hr

Lorenzo C.

Degree: Biomedical Sciences with Honours in Infectious Diseases (Bachelors) - Edinburgh University

Subjects offered: Physics, Chemistry+ 1 more


“Hey! I'm Lorenzo and I study Biomedical Sciences with an honours in Infectious Diseases at the University of Edinburgh. I'd be happy to help you with Biology, Chemistry and Physics at GCSE or at A-Level.  I have previous experience tu...”

You may also like...

Posts by Lorenzo

Although carbon dioxide is a linear molecule it is still a greenhouse gas. Explain why that is.

Describe the photoelectric effect and what it tells us about the properties of light .

Garlic contains a chemical called Allicin which has antimicrobial properties. Describe how this could have occurred through natural selection.

Other A Level Physics questions

Describe the photoelectric effect.

A model truck A of mass 1.2 kg is travelling due west with a speed of 0.90 m/s . A second truck B of mass 4.0 kg is travelling due east towards A with a speed of 0.35 m/s .

Atmospheric Pressure is about 1.0x10^5 Pa. What is the downward force of the air on a desktop of surface area 1m^2?

Explain how fluorescent tubes work

View A Level Physics tutors


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