Chapter 27, Problem 33P

(III) A proton moving with speed υ = 1.3 × 10⁵ m/s in a field-free region abruptly enters an essentially uniform magnetic field $B=0.850T\left(\stackrel{\to }{B}\perp \stackrel{\to }{v}\right)$. If the proton enters the magnetic field region at a 45° angle as shown in Fig. 27–46, (a) at what angle does it leave, and (b) at what distance x does it exit the field?