HARD
JEE Main/Advance
IMPORTANT
Earn 100

A spherical ball of radius 3.0×104 m and density 104 kg m-3 falls freely under gravity through a distance h before entering a tank of water. If after entering the water the velocity of the ball does not change, find h. Viscosity of water is 9.8×106 N s m-2. [g= 9.8 m s-2, ρw=1000 kg m-3]

Important Questions on Viscosity and Surface Tension

EASY
JEE Main/Advance
IMPORTANT

An oil drop falls through the air with a terminal velocity of 5 × 104 m s-1. The radius of the drop will be: η=3.6×10-5 N s m-2, ρoil=900 kg m-3.,g=10 m s-2

Neglect the density of air as compared to oil.

EASY
JEE Main/Advance
IMPORTANT
The terminal velocity of a sphere moving through a viscous medium is:
EASY
JEE Main/Advance
IMPORTANT
A sphere is dropped gently into a medium of infinite extent. As the sphere falls, the force acting downwards on it
EASY
JEE Main/Advance
IMPORTANT
A solid sphere falls with a terminal velocity of 10 m s-1 in air. If it is allowed to fall in vacuum,
MEDIUM
JEE Main/Advance
IMPORTANT
The following observations were taken for determining surface tension T of water by capillary method. Diameter of capillary d=1.25×10-2 m, rise of water h=1.45×10-2 m. Using g=9.80 m s-2 and the simplified relation, T=rhg2×103 N m-1, the possible error in surface tension is closest to
MEDIUM
JEE Main/Advance
IMPORTANT
Two hail stones with radii in the ratio of 1 : 2 fall from a great height through the atmosphere. Then the ratio of their momentum after they have attained terminal velocity is
EASY
JEE Main/Advance
IMPORTANT

A spherical ball is dropped in a long column of viscous liquid. Which of the following graphs represent the variation of

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(i) gravitational force with time.

(ii) viscous force with time.

(iii) net force acting on the ball with time.

EASY
JEE Main/Advance
IMPORTANT
A small steel ball falls through a syrup at constant speed of 10 cm s-1. If the steel ball is pulled upwards with a force equal to twice its effective weight, how fast will it move upwards?