BITSAT 2019 Physics Heat and Thermodynamics Revision Quiz 1 for JEE & BITSAT Exams

Question 1

Jet aircrafts fly at altitudes above 30,000 ft where the air is very cold at -40

and the pressure is 0.28 atm. The cabin is maintained at 1 atm pressure by means of a compressor which exchanges air from outside adiabatically. In order to have a comfortable cabin temperature of 25

, we will require in addition:

Question 2

In a thermally isolated system, two boxes filled with an ideal gas are connected by a valve. When the valve is in closed position, states of the box 1 and 2, respectively, are (1 atm, V, T) and (0.5 atm, 4V, T). When the valve is opened, the final pressure of the system is approximately

Question 3

Temperature of two stars are in ratio 3 : 2. If wavelength of maximum intensity of first body is 4000

, what is the corresponding wavelength of the second body?

Question 4

If a metallic sphere gets cooled from 62°C to 50^oC in 10 min and in the next 10 min gets cooled to 42 °C, then the temperature (in °C) of the surroundings is

Question 5

A, B and C are the three identical conductors but made from different materials. They are kept in contact as shown.
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Their thermal conductivities are K, 2K and $Description: E:\KCET-1-Feb\KARNATAKA-PAPER-2012_files\image051.png$ . The free end of A is at 100 ºC and the free end of C is at 0 ºC. During steady state, the temperature of the junction of A and B is nearly..... ºC.

Question 6

A large cylindrical rod of length L is made by joining two identical rods of copper and steel of length

each. The rods are completely insulated from the surroundings. If the free end of copper rod is maintained at 100°C and that of steel at 0°C then the temperature of junction is (Thermal conductivity of copper is 9 times that of steel)

Question 7

A container with rigid walls is covered with perfectly insulating material. The container is divided into two parts by a partition. One part contains a gas while the other is fully evacuated (vacuum). The partition is suddenly removed. The gas rushed to fill the entire volume and comes to equilibrium after a little time. If the gas is not ideal,