Question

A beam of protons with speed 4 × 10⁵ ms^–1 enters a uniform magnetic field of 0.3 T at an angle of 60° to the magnetic field. The pitch of the resulting helical path of protons is close to (Mass of the proton = 1.67 × 10^–27 kg, charge of the proton = 1.69 × 10^–19 C) 

(1) 2 cm 

(2) 12 cm 

(3) 5 cm 

(4) 4 cm

Answer 1

Answer is (4) 4 cm

Pitch = v cosθ x \(\frac{2\pi m}{qB}\)