An electron follows a circular path (radius = 15 cm) in a uniform magnetic field (magnitude = 3.0 G). What is the period of this motion?
A) 0.12 μs
B) 1.2 ms
C) 0.18 μs
D) 1.8 ms
E) 1.8 μs

Question

Quizplus · Accepted Answer

Explanation:The period of the motion is given by:T = 2πr / vwhere r is the radius of the circular path and v is the speed of the electron. The speed of the electron is given by:v = eB / mwhere e is the charge of the electron, B is the magnitude of the magnetic field, and m is the mass of the electron. Substituting these expressions into the equation for the period, we get:T = 2πr / (eB / m)Plugging in the given values, we get:T = 2π(0.15 m) / (1.6 × 10^-19 C)(3.0 × 10^-4 T) / (9.1 × 10^-31 kg)T = 0.12 μs

An Electron Follows a Circular Path (Radius = 15 Cm)