A 10 kW drilling machine is used to drill a bore in a small aluminium block of mass 8.0 kg. How much is the rise in temperature of the block in 2.5 minutes, assuming 50% of power is used up in heating the machine itself or lost to the surroundings. Specific heat of aluminium ` = 0.91 J g^-1 ^@C^-1`

A coper block of mass 2.5 kg is heated in a furnace to a temperature of 500 ^@C and then placed on a large ice block. What is the maximum amount of ice that can melt? (specific heat of copper = 0.39 J g^-1 C^-1 , heat of fusion of watter = 335 J g^-1 ).

A thermocole box is a cheap and effieicnet method for storing small quantity of cooked food in summer in particular. A cubical box of side 30 cm has a thickness of 5 cm. If 4 kg of ice are put in a box. Estimate the amount of ice remaining after 6 h. The outside temperature 45^@C , and coefficient K = 0.01 J s^-1 m^-1 k^-1 [Heat of fusion of water = 335 xx 10^3 J kg^-1] .

A heating element using nichrome connected to a 230 V supply draws an initial current of 3.2 A which settles after a few seconds to a steady value of 2.8 A. What Is the steady temperature of the heating element If the room temperature is 27.0^@C ? Temperature coefficient of resistance of nichrome averaged over the temperature range involved is 1.70 xx 10^-4@C .

Shown in the figure a spring fixed at the bottomm end of all incline of inclination 37^@ . A small block of mass 2 kg starts slipping down the incline form a point 4.8 m aaway from the spring. The block compresses the spring by 20 cm, stops momentarily and then rebounds through a distance of 1 m up the incline. Find the spring constant of the spring Take g = 10 ms^-2

In a refrigerator, one removes heat from a lower temperature and deposits to the surroundings at a higher temperature. In this process, mechanical work has to be done, which is provided by an electric motor. If the motor is of 1kW power, and heat is transferred from -3^@ C to 27^@C , find the heat taken out of the refrigerator per second assuming its efficiency is 50% of a perfect engine.

The heat of combustion of ethane gas is 373 K Cal per mole. Assuming that 50% of heat is lost, how many litres of ethane measured at S.T.P. must be burnt to convert 50 kg of water at 10^@C to steam at 100^@C ? One mole of gas occupies 22.4 litres at S.T.P. Latent heat (L) of steam = 2.25 xx 10^6 J k^-1 .

Gasoline has an enthalpy of combustion 24000 kJ/mol gallon. When gasoline burns in an automobile engine, approximately 30% of the energy released is used to produce mechanical work. The remainder is lost as heat transfer to the engine's cooling system. As a start on estimating how much heat transfer is required, calculate what mass of water could be heated from 25^(@)C to 75^(@)C by the combustion of 1.0 gallon of gasoline in an automobile? (Given : C(H_(2)O)=4.18 J//g^(@)C ) a) 34.45 kg b) 80.383 kg c) 22 kg d) 224 kg

A heating coil is immersed in a 100 g sample of H_(2)O (l) at a 1 atm and 100^(@) C in a closed vessel. In this heating process , 60% of the liquid is converted to the gaseous form at constant pressure of 1 atm . The densities of liquid and gas under these conditions are 1000 kg//m^(3) and 0.60 kg//m^(3) respectively . Magnitude of the work done forthe process is : (Take : 1L-atm= 100J)

In Millikan’s oil drop experiment, what is the terminal speed of an uncharged drop of radius 2.0xx 10^5 m and density 1.2xx 10^3 kg m^-3 . Take the viscosity of air at the temperature of the experiment to be 1.8xx 1 0^-5 Pa s. How much is the viscous force on the drop at that speed ? Neglect buoyancy of the drop due to air

When sulphur ( in the form of S_(8)) is heated at temperature T , at equilibrium , the pressure of S_(8) falls by 30% from 1.0 atm , because S_(B)(g) in partially converted into S_(2)(g) . Find the value of K_(P) for this reaction.