Given a charge q, current I and permeability of vacuum 0. Which of the following quantity has the dimension of momentum ?
- qI/ 0
- q2 0 I
- q 0/I
- q 0 I
Answer
(4) q 0 I
Solution
From Fl = 0 I1 I22 d: [ 0] = [F][I]2 = [ M L T-2 A-2]
[q] = [A T], [I] = [A]
[q 0 I] = [A T][ M L T-2 A-2][A]
= [ M L T-1] = dimension of momentum
(Check: [qI/ 0] = [ M-1 L-1 T3 A4], [q2 0 I] = [M L A T0], [q 0/I] = [ M L T-1 A-2])
Answer: (4)