MAH-MHT CET (PCM/PCB) entrance exam Question Bank Solutions for Physics

When a solid ball of volume V is released in a viscous liquid it experiences a viscous force F. If the solid ball of the same material of volume V/2 is released in the liquid then the viscous force will be (where `eta` = coefficient of viscosity) ____________.

The viscous force acting on a small spherical rain drop falling through stormy air cannot be calculated using Stoke's law because ____________.

What will be the approximate terminal velocity of a rain drop of diameter 1.2 x l0^-3 m, when density of rainwater ≈ l0³ kgm^-3 and the co-efficient of viscosity of air ≈ 1.8 x l 0^-5 Nsm^-2? 

A metal sphere of radius 'R' and density 'ρ₁' is dropped in a liquid of density 'σ' moves with terminal velocity 'v'. Another metal sphere of same radius and density 'ρ₂' is dropped in the same liquid, its terminal velocity will be ______.

If α is the coefficient of performance of a refrigerator and 'Q₁' is heat released to the hot reservoir, then the heat extracted from the cold reservoir 'Q₂' is ______.

A rod of weight W is supported by two parallel knife edges A and B and is in equilibrium in a horizontal position. The knives are at a distance d from each other. The centre of mass of the rod is at distance x from A. The normal reaction on A is ____________.

Two spheres of equal masses but radii r₁ and r₂ are allowed to fall in a liquid of infinite column. The ratio of their terminal velocities are ____________.

A small sphere of mass m is dropped from a great height. After it has fallen 100 m, it has attained its terminal velocity and continues to fall at that speed. The work done by air friction against the sphere during the first 100 m of fall is ______.

A drop of radius 1.5 x 10^-5 and density 2 x 10³ kg/m³ falls through air. The viscosity of air is 1.8 x 10^-5 N s/m². Neglecting buoyancy due to air, the terminal speed of the drop is ____________.

A drop of radius 4 x 10^-5 m and density 2.5 x 10³ kg/m³ falls through air. The viscosity of air is 1.96 x 10^-5 N s/m² . Neglecting buoyancy due to air, the terminal speed of the drop is ____________.

Two small spherical metal balls, having equal masses, are made from materials of densities `rho_1` and`rho_2  (rho_1 = 8rho_2)` and have radii of 1 mm and 2 mm, respectively, they are made to fall vertically (from rest) in a viscous medium whose coefficient of viscosity equals `eta` and whose density is `0.1rho_2` The ratio of their terminal velocities would be, ____________.

A uniform bar RS weighs 100 g and is 80 cm long. From the end R, two masses 50 g and 100 g are hung from the bar at a distance of 10 cm and 60 cm respectively. If the bar is to remain horizontal when balanced on a knife-edge, its position is ____________.

Liquid is filled in a vessel which is kept in a room with temperature 20° C. When the temperature of the liquid is 80° C, then it loses heat at the rate of 90 cal/s. What will be the rate of loss of heat when the temperature of the liquid is 40° C?

Eight identical drops of water falling through air with uniform velocity of 10 cm/s combine to form a single drop of big size, then terminal velocity of the big drop will be ______.

The radii of the two spheres P and Q of same material falling in the viscous liquid are in the ratio 3 : 2, their terminal velocities (P to Q) are in the ratio ______.

A small spherical solid ball is dropped from a great height in a viscous liquid. Its journey in the liquid is best described in the diagram given below by the ____________.

5 m long see-saw remains horizontal when two children weighing 20 kg and 30 kg respectively sit at two ends. Where is the see-saw supported?

If 1 g of a steam which is at 100°C starts melting then how much ice will remain at 0° C? (Latent heat of ice = 80 cal/g and latent heat of steam= 540 cal/g)

A small metal ball of mass ‘m’ is dropped in a liquid contained in a vessel, attains a terminal velocity ‘v’. If a metal ball of same material but of mass ‘8m’ is dropped in same liquid then the terminal velocity will be ______.

A see-saw of length 6 m is pivoted at its centre. A child of mass 20 kg is sitting at one of its ends. Where should another child, of mass 30 kg, sit on the other end from the centre of see-saw, so that it is balanced?