JEE · NEET Previous Year Question

A beam of protons with speed $4\times {10}^5{\text{ms}}^{-1}$ enters a uniform magnetic field of $0.3T$ 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 $=1.67\times {10}^{-27}\text{kg}$ charge of the proton $=1.69\times {10}^{-19}C\text{)}$

Topic: JEE PYQ

Answer: D. Full step-by-step solution below.