A proton is projected perpendicularly into a magnetic field that has a
magnitude of 0.50 T. The field is then adjusted so that an electron will follow the
exact same circular path when it is projected perpendicularly into the field with
the same velocity that the proton had. What is the magnitude of the field used for
the electron?
The radius of curvature of a particle is given by . Thus,
The magnetic field is ‐2.7 x 10‐4 T (the negative sign indicates the field is reversed).
m
r
q B
=
υ
( )
( )
( )
31
27
9.11 10 kg
1.67 10
0.50T
kg
p e
p e
p e e
p e
e
e
p
B p
m m
r r
eB e B
m m m
eB e B
B
m
B
−
−
⎛ ⎞