The force F on a sphere of radius r moving in a medium with velocity v is given by…

Q: The force F on a sphere of radius r moving in a medium with velocity v is given by F = 6π η r v . The dimensions of η are

(a) [ML–3]

(b) [MLT–2]

(c) [MT–1]

(d) [ML–1T–1]

Ans: (d)

Sol: $\displaystyle \eta = \frac{F}{6\pi r v}$

$\displaystyle \eta = \frac{MLT^{-2}}{ L .LT^{-1}}$

$\displaystyle \eta = [M L^{-1}T^{-1}]$