Alpha particles of charge q = +2e and mass m = 6.6 10-27 kg are emitted from a radioactive source at a speed of 1.3 107 m/s. What magnetic field strength would be required to bend these into a circular path of radius r = 0.23 m?
3 Answers
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w = v/r = 56521739 rad/s
B = mw/q = 1.16418 T
1st answer used wrong value for q(e), it's 1.602E-19 C.
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Force on an alpha particle by the magnetic field = Bqv
B - Magnetic field strength
q - charge of the particle
v - velocity of the particle
Force towards the center when moving in a circular path = mv^2/r
m - Mass
v - Velocity
r - Radius
charge of one electron = 6.102 x 10^-19 C
Bqv = mv^2/r
B x ( 6.102 x 10^-19 x 2 ) x 1.3 x 10^7 = [ 6.6 x 10^-27 x ( 1.3 x 10^7 )^2 ] / 0.23
B = 0.3056 H
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Charge Of Alpha Particle
