A motor pump rated 400 W operate for 2 min and 40 sec and in doing so, raises 200 kg of water of the top of a building. If g = 10m, calculate the height of the building.

18 g of a compound is dissolved in 10 kg of water so that the resulting solution freezes at - 8^(@) C . If K_(f) for water = 1 . 86 K/m . Calculate the molecular mass of the compound

A pump on the ground floor of a building can pump up water to fill a tank of volume 30 m^3 in 15 min. If the tank is 40 m above the ground, and the efficiency of the pump is 30%, how much electric power is consumed by the pump ?

An electric motor operating at 200 V draws a current of 5 A at its full speed. The resistance of the armature is 10 Omega . Calculate the back e.m.f. and efficiency of the motor?

35 g of compound is added in 1 kg of water so that the resulting solution freezes at - 10^(@) C . If K_(f) for water = 1. 86 K/m . Calculate the molecular mass of the compound

A brass boiler has a base area of 0.15 m^2 and thickness 1.0 cm. It boils water at the rate of 6.0 kg/min. When placed on a gas stove. Estimate the temperature of the part of the flame in contact with boiler. Thermal conductivity of brass = 109 j s^-1 m^-1 ^@C^-1 .

Water is leaking form a conical funnel at the rate of 5cm^3//s , If the radius of the base of funnel is 5 cm and height 10 cm, find the rate at which the water level is dropping when it is 2.5 cm from the top. Is leaking of water leads to wastage of water? Should we do everything to ssave this natural resource?

The power of a motor pump is 5 kW. How much water per minute the pump an raise to height of 20 m ? Take g = 10ms ^-2 .

Four men lift a 250 kg box to a height of 1 m and hold it without raising or lowering it.How much work is done in just holding it? (Take g=10ms^(-2)).