Q. A beam of protons with speed $4 \times 10^{5} ms ^{-1}$ enters a uniform magnetic field of $0.3 T$ at an angle of $60^{\circ}$ to the magnetic field. The pitch of the resulting helical path of protons is close to: (Mass of the proton $=1.67 \times 10^{-27} kg$, charge of the proton $=1.69 \times 10^{-19} C$
Solution: