Question

Flag An alpha particle (consisting of two protons and two neutrons) is moving in a circle at a constant speed, perpendicular to a uniform magnetic field applied by some current-carrying coild. The alpha particle makes an clockwise revolution every 88 ns. If the speed is small compared to the speed of light, what is the magnitude B of the magnetic field made by the coils

Answer 1

Answer:

m = 4 At Mass units = 4 * 1.66E-27 kg = 6.64E-27 kg  mass of particle

q = 2 * 1.60E-19 C = 3.2E-19 C     total charge of alpha particle

T = 8.8E-8 s     period of 1 revolution

F = q V B      magnetic force

F = m V^2/ R     centripetal acceleration

q V B = m V^2 / R

B = m V / (q * R)

T = 2 pi R / V     time for 1 revolution

R = V T / (2 pi)

B = (m V / q) * 2 pi / (V T) = 2 pi m / (q T)

B = 2 pi * 6.64E-27 / (3.2E-19 * 8.8E-8) = 1.48

B = 1.48 W/m^2