22.4 Exercise 12

(a) A cosmic ray proton moving toward the Earth at $\text{5}.\text{00} \times \text{10}^{7} \text{m}/\text{s}$ experiences a magnetic force of $1 . \text{70} \times \text{10}^{- \text{16}} \text{N}$. What is the strength of the magnetic field if there is a $\text{45}º$ 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.