Protons and helium nuclei from the Sun pass into the Earth’s atmosphere above the poles, where the magnetic flux density is 6.0 × 10⁻⁵ T. The particles are moving at a speed of 1.0 × 10⁶ m s⁻¹ at right angles to the magnetic field in this region. The magnetic field can be assumed to be uniform.

a. Calculate the radius of the path of a proton as it passes above the Earth’s pole.

Mass of a helium nucleus = 6.8 × 10⁻²⁷ kg
Charge on a helium nucleus = 3.2 × 10⁻¹⁹ C

b. Sketch a diagram to show the deflection caused by the magnetic field to the paths of a proton and of a helium nucleus that both have the same initial velocity as they enter the magnetic field.