Heat and Thermodynamics · Physics · VITEEE

A copper sphere cools from $$82^{\circ} \mathrm{C}$$ to $$50^{\circ} \mathrm{C}$$ in 10 minutes and to $$42^{\circ} \mathrm{C}$$ in the next $$10 \mathrm{~min}$$. Calculate the temperature of the surrounding?

Two gases occupy two containers $$A$$ and $$B$$. The gas in $$A$$ of volume $$0.20 \mathrm{~m}^3$$, exerts a pressure of $$1.40 \mathrm{~MPa}$$ and that in $$B$$, of volume $$0.30 \mathrm{~m}^3$$ exerts a pressure of $$0.7 \mathrm{~MPa}$$. The two containers and united by a tube of negligible volume and the gases are allowed to exchange. Then, if the temperature remains constants. the final pressure in the container will be (in MPa).

0.5 mole of an ideal gas at constant temperature $$27^{\circ} \mathrm{C}$$ kept inside a cylinder of length $$L$$ and cross-section $$A$$ closed by a massless piston. The cylinder is attached with a conducting rod of length L$$_1$$ cross-section area $$(1 / 9) \mathrm{m}^2$$ and thermal conductivity $$k_1$$ whose other end is maintained at $$0^{\circ} \mathrm{C}$$. If piston is moved such that rate of heat flow through the conduction rod is constant then velocity of piston when it is at height $$L / 2$$ from the bottom of cylinder is (neglect any kind of heat loss from system)

An electrically heated coil is immersed in a calorimeter containing $$360 \mathrm{~g}$$ of water at $$10^{\circ} \mathrm{C}$$. The coil consumes energy at the rate of $$90 \mathrm{~W}$$. The water equivalent of calorimeter and coil is $$40 \mathrm{~g}$$. The temperature of water after $$10 \mathrm{~min}$$ is

If 2 moles of an ideal monoatomic gas at temperature $$T_0$$ is mixed with 4 moles of another ideal monoatomic gas at temperature $$2 T_0$$, then the temperature of the mixture is

If the ratio of specific heat of a gas at constant pressure to that at constant volume is $$\gamma$$, the change in internal energy of the given mass of gas, when the volume changes from $$V$$ to $$2 V$$ at constant pressure $$p$$ is

From Wien's displacement law, $$\lambda_m T=$$ constant $$=0.00289 \mathrm{~m}-\mathrm{K}$$

Radiation from moon givens $$\lambda_m=4700 \mathop A\limits^o$$ and another wavelength of $$14 \times 10^{-6} \mathrm{~m}$$. Out of the following which conclusion(s) drawn is/are correct with the given information regarding the moon and the sun?

1. Sun radiations are reflected from moon's disc.

2. The temperature of moon's surface is $$207 \mathrm{~K}$$

3. The temperature of the sun is $$6160 \mathrm{~K}$$.

If two metallic plates of equal thickness and thermal conductivities $$K_1$$ and $$K_2$$ are put together face to face and a common plate is constructed, then the equivalent thermal conductivity of this plate will be

The zeroth law of thermodynamics for three systems $$A, B$$ and $$C$$ in contact demands that

The velocity of sound in a gas is $$1300 \mathrm{~m} / \mathrm{s}$$ at STP and specific heat at constant pressure is $$6.84 \mathrm{~cal} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}$$. The rms velocity at STP is $$(R=1.98 \mathrm{~cal} \mathrm{~K}^{-1} \mathrm{~mol}^{-1})$$

The efficiency of a Carnot engine kept at the temperatures of $$27^{\circ} \mathrm{C}$$ and $$127^{\circ} \mathrm{C}$$ is

According to equipartition law of energy each particle in a system of particles have thermal energy $$E$$ equal to