CHOSE ATLEAST ONE NUMERICAL AND ONE THEORY FROM EACH CHAP. DO ANY 10

Q.1.When 1m^{3} of water is converted into 1671 m^{3} of steam at atmospheric pressure and 100^{o}C temperature. The latent heat of vaporisation of water is 2.3×10^{6} J/kg. If 2kg of water is converted into at atmospheric temperature and 100^{o}C, then how much will be increase in internal energy? (d=10^{3} kgm^{-3} ,atm pressure=1.01×10^{5}) .

Q.2.From how much height a piece of 10gm of ice must be dropped so that it will convert into water vapour on touching the surface of ground ?

Q.3.A 10kg hammer fall with a velocity of 2 m/s on a piece of lead of 0.6 kg at 27^{o}C. Find the increase in temperature of the lead after 1000 stroke and also find the number of stroke required to melt it.

Q.4.A mole of ideal gas at atmospheric pressure is compressed adiabatically from 9L to 5L. Calculate the molar specific heat gas ratio if C_{v}=3R/2 and work done in the above process.

Q.5.A Carnot engine whose low temperature reservoir is at 7^{o}C has an efficiency of 50%. It is desired to increase the efficiency to 70%. By how much temperature must the high –temperature reservoir be raised.

Q.6. Three bar of equal length has conductivities in the ratio of 2:3:4. If the end of the rods are kept at 200^{o}C and 18^{o}C.then find the temperature between the junctions of three rods.

Q.7.A body cools in 7 minute from 60^{o}C to 40^{o}C. what will be the temperature after next 7 minutes? The temperature of surrounding is 10^{o}C. Assuming that the newton law of cooling is good throughout the process.

Q.8.The temperature of the surface of a silver sphere of radius 5 cm is 527^{o}C. If the emissivity of the surface is 0.04. Find out the energy emitted per second from the surface of the sphere.

Q.9.If the spectral distribution of the sun ‘s spectrum at 5777^{o}C maximum occurs at 4750 A . then what will be temperature of star for which maximum spectral distribution occur at 9500 A.

Q.10. State the law of equipartition of energy . Using this law show that perfect gas has f degree of freedom and finds the gas ratio for different atomicity of gas?

Q.11. Derive the expression for external work done by an ideal gas in isothermal expansion.

Q.12. Describe Carnot’s heat engine and obtain the expression for it efficiency in terms of heat and temperature.

Q.13. Find the expression for the equivalent conductivity of two different metal joined in series.

Q.14. A metallic key of length L area A conductivity K is used to close the pipe containing hot water at 100^{o}C. Then find the relation for the specific heat of the water?

Q.15. Define solar constant and how does one estimate the surface temperature of the sun?

Q.16.Define perfect black body .Draw the spectral distribution curves of black body radiation and write the effect of rise in temp.

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