Question

If $M = mass , L =$ length, $T =$ time and $I=$ electric current, then the dimensional formula for electrical resistance $R$ is given by:

• A. $[R]=\left[M^{1} L^{2} T^{-3} I^{-2}\right]$
• B. $[R]=\left[M^{1} L^{2} T^{-3} I^{2}\right]$
• C. $[R]=\left[M^{1} L^{2} T^{1} I^{2}\right]$
• D. $[R]=\left[M^{-1} L^{2} T^{-3} I^{-2}\right]$

Answer 1

Answer: (A)

$R=\frac{V}{I}$ (ohms law)
$R=\frac{W}{q I}=\frac{\left[M L^{2} T^{-2}\right]}{I T I}$
$[R]=\left[M L^{2} T^{-3} I^{-2}\right]$