State the change to a nucleus of X when it emits an alpha-particle.
A radiation detector is operating in a laboratory with no radioactive samples present. It is switched on and shows an average count rate of 22 counts per minute. State why the radiation detector shows a count rate.
A sample of isotope X is placed $2\,\text{cm}$ from the detector and the displayed reading is 8000 counts per minute. The sample is then moved to a distance of $10\,\text{cm}$ from the detector. The reading returns to an average value of 22 counts per minute. Explain why the reading returns to the original value.
On Fig. 6.1, draw an arrow through point J to show the direction of the force acting on the alpha-particle at J.
Work out the direction of the magnetic field and place a tick (✓) in the box that shows this direction.
Explain whether this force does work on the alpha-particle while it moves along the circular path.