Question

18. Dimensions of resistance in an electrical circuit, in
terms of dimension of mass M, of length L, of time
T and of current I, would be
6 br [AIPMT (Prelims)-2007]
(1) [ML2T-31-2]
(2) [ML2T-31"]
(3) [ML2T-2]
OST
(4) [ML2T-11-']​

Answer 1

Ohm's law: R=

I

V

Also, W=Vq⟹V=

q

W

(where, q=It)

⟹ R=

qI

W

=

I

2

t

W

Dimensions of work done, W=[ML

2

T

−2

]

∴ Dimension of resistance, R=

I

2

T

[ML

2

T

−2

]

=[ML

2

T

−3

I

−2

]