Alpha particles of charge q = +2 e and mass m = 6.6 10 -27 kg are emitted from a radioactive source at a speed of 1.5 10 7 m/s.

Alpha particles of charge q = +2e and mass m = 6.6 ✕ 10-27 kg are emitted from a radioactive source at a speed of 1.5✕ 107 m/s. What magnetic field strength would be required to bend them into a circular path of radius r = 0.26 m?