## Question

A drilling machine of power *P* watts is used to drill a hole in copper block of mass *M* kg. If the specific heat of a copper is *s* J and 40% of the power is lost due to heating of the machine, the rise in the temperature of the block in *T* seconds will be (in ^{o}C)

### Solution

Useful power available = 60% 0f *P = *0.6 *P* watts. Therefore, energy consumed in *T* seconds = 0.6 *PT* joules. This energy is used up in heating block. If the rise in temperature , then

or

#### SIMILAR QUESTIONS

A glass flask of volume 500 cm^{3} is completely filled with a liquid at 0^{o}C. When it is placed in boiling water at 100^{o}C, 75 cm^{3} of the liquid overflows. If the coefficient of cubical expansion of glass is ^{o}C^{-1}, what is the coefficient of cubical expansion of the liquid?

A thin metal square plate has length *l*. When it is heated from 0^{o}C to 100^{o}C, its length increases by 1%. What is the percentage increase in the area of the plate?

The density of a liquid of coefficient of cubical expansion . When the liquid is heated to a temperature *T*, the change in density will be

Two rods of different materials having coefficient of thermal expansion and Young’s modulii *Y*_{1} and *Y*_{2} are fixed between two rigid and massive walls. The rods are heated to the same temperature. If there is no bending of the rods, the thermal stresses developed in them are equal provided

300 g of water at 25^{o}C is added to 100 g of ice at 0^{o}C. The final temperature of the mixture is

100 g of ice at 0^{o}C is mixed with 100 g of water 80^{o}C. The final temperature of the mixture will be

Steam at 100^{o}C is passed into 1.1 kg of water contained in a calorimeter of water equivalent 0.02 kg at 15^{o}C till the temperature of the calorimeter rises to 80^{o}C. The mass of steam condensed in kilogram is

If there are no heat losses, the heat released by the condensation of *x*grams of steam at 100^{o}C into water 100^{o}C converts *y* grams of ice at 0^{o}C into water at 100^{o}C. The ratio *y*/*x *is nearly

One mole of oxygen is heated from 0^{o}C, at constant pressure, till its volume increases by 10%. The specific heat of oxygen, under these conditions is 0.22 cal g ^{– 1 }K^{ – 1}. The amount of heat required (in joules) is

A geyser, operating on LPG (liquefied petroleum gas) heats water flowing at the rate of 3.0 litres per minute, from 27^{o}C to 77^{o}C. If the heat of combustion of LPG is , how much fuel in grams is consumed per minute?