Question

The viscous force on a small sphere of radius R moving in a fluid varies as

• A. $\propto R^2$
• B. $\propto R$
• C. $\propto (1/R)$
• D. $\propto (1/R{)}^2$

Answer 1

Answer: (B)

According to Stokes' law
Viscous force, $F=6\pi \eta Rv$,
so $F\propto R$