Chapter 22: Magnetism

If a cosmic ray proton approaches the Earth from outer space along a line toward the center of the Earth that lies in the plane of the equator, in what direction will it be deflected by the Earth’s magnetic field? What about an electron? A neutron?

(a) A cosmic ray proton moving toward the Earth at $\mathbf{5}\mathbf{.}\mathbf{00}\mathbf{\times }{\mathbf{10}}^{\mathbf{7}}\mathbf{}\mathit{m}\mathbf{/}\mathit{s}$experiences a magnetic force of $\mathbf{1}\mathbf{.}\mathbf{70}\mathbf{\times }{\mathbf{10}}^{\mathbf{‐}\mathbf{16}\mathbf{}\mathbf{N}}$. What is the strength of the magnetic field if there is a ${45}^{\circ }$ angle between it and the proton’s velocity? (b) Is the value obtained in part (a) consistent with the known strength of the Earth’s magnetic field on its surface? Discuss.