Magnetic Fields Radiation
Physics: Cambridge International GCSE Supplement, topic 5.3.4
Radiation in Magnetic Fields
Different types of radiation behave differently in magnetic fields.
Gamma rays
- Gamma rays are not affected by magnetic or electric fields.
- They travel in a straight line through both types of field.
Beta radiation
- Beta particles are negatively charged because they are electrons.
- Because they are charged, they change path in a magnetic or electric field.
- A magnetic field deflects beta particles more than alpha particles because they have less mass.
Alpha particles
- Alpha particles are positively charged because they contain 2 protons.
- Because of this, they change path in a magnetic or electric field.
- Alpha particles are deflected less than beta particles because they are more massive (have more mass) and are harder to pull.
The left-hand rule
- Because beta particles are electrons, their motion is in the opposite direction to conventional current.
- So, point your second finger in the opposite direction to the particle’s actual velocity.
- Now your thumb gives the direction of the force on the particle.
- This is the path the beta particle will be deflected in the magnetic field.
Test yourself on Magnetic Fields Radiation
What happens to gamma radiation in a magnetic field?
Why are alpha and beta particles deflected in a magnetic field?
Which rule predicts the direction of alpha particles in a magnetic field?
Types of Emission