A pump on an average delivers 300 kg of water at a height of 10 cm in 1 minute.Calculate the average power of the pump in h.p.

A refrigerator has to transfer an averageof 200 Joule ofheat per sec from temperature - 10^@C to +25^@C . Calculate the average power consumed assuming ideal reversible cycle and no other losses.

An electric pump is used to full an overhead tank of capacity 9m^3 kept at a height of 10 m above the ground. If the pump takes 5 minutes to fill the tank by consuming 10 KW power , What is the efficiency of the engine ?

A 20 gram bullet moving at 300 m/s stops after penetrating 3 cm of bone. Calculate the average force it exerts.

In the Bohr model of hydrogen atom the electron revolves around the nucelus at the rate of 36 xx 10^16 revoltuions per minute. Calculate the average current at a point on the orbit.

Two insulated charged metallic spheres A and B have their centres separated by a distance of 50 cm in air (1) calculate the force of répulsion between them, if the charge on each is +5.0xx 10 ^(-8) C (ii ) calculate the force of repulsion between them when the two spheres are placed in water. (dielectric constant of water is 81.0)

For the reaction, R to P , the concentration of a reactant changes from 0.03 M to 0.02 M in 25 min. calculate the average rate of reaction using units of time both in minutes and seconds.

A rubber ball of mass 0.05 kg falls from a height of 1 m and rebounds to a height of 0.5 m. Find the average force when their contact was 0.1 sec.