16. Spherical balls of radius ‘r’ are falling in a viscous fluid of viscosity
‘η‘ with a velocity ‘v‘. The retarding viscous force acting on the spherical ball is
(a) Inversely proportional to ‘r‘ but directly proportional to velocity ‘v‘
(b) Directly proportional to both radius ‘r‘ and velocity ‘v‘
(c) Inversely proportional to both radius ‘r‘ and velocity ‘v‘
(d) Directly proportional to ‘r‘ but inversely proportional to ‘v‘
Answer-b
(7)