Two protons are projected into different magnetic fields B1 and B2 respectively. The velocity v1 is double the velocity v2. What will be the ratio B2 : B1 if the two radii are equal ?

1 : 2 2 : 1 1 : 1 3 : 2

1 : 2

v1 = 2 v2 v1 : v2 = 2 : 1 r1 = m v1/qB1 ; r2 = m v2/qB2 r1 = r2  v1/B1 = v2/B2 v1/v2 = B1/B2 = 2 : 1