Test: JEE Main 35 Year PYQs- Heat & Thermodynamics - JEE MCQ

Which of the following is more close to a black body?

Cooking gas containers are kept in a lorry moving with uniform speed. The temperature of the gas molecules inside will

If mass-energy equivalence is taken into account, when water is cooled to form ice, the mass of water should

At what temperature is the r.m.s velocity of a hydrogen molecule equal to that of an oxygen molecule at 47°C?

Even Carnot engine cannot give 100% efficiency because we cannot

1 mole of a gas with γ = 7/5 is mixed with 1 mole of a gas with γ = 5/3, then the value of g for the resulting mixture is

Two spheres of the same material have radii 1 m and 4 m and temperatures 4000 K and 2000 K respectively. The ratio of the energy radiated per second by the first sphere to that by the second is

“Heat cannot by itself flow from a body at lower temperature to a body at higher temperature” is a statement  or consequen ce of

During  an adiabatic process, the pressure of a gas is found to be proportional to the cube of its absolute temperature.
The ratio CP /CV for the gas is

Which of the following parameters does not characterize the thermodynamic state of matter?

A Carnot engine takes 3 *10 ⁶ cal. of heat from a reservoir at 627^o C , and gives it to a sink at 27 ^o C . The work done by the engine is

The earth  radiates in the infra-red region of the spectrum. The spectrum is correctly given by

According to Newton’s law of cooling, the rate of cooling of a body is proportional to ( Δθ)ⁿ , wher e Δθ is the difference of the temperature of the body and the surroundings, and n is equal to

One mole of ideal monatomic gas ( γ = 5 / 3) is mixed with one mole of diatomic gas (γ = 7 / 5) . What is g for the mixture? γ Denotes the ratio of specific heat at constant pressure, to that at constant volume

If the temperature of the sun were to increase from T to 2T and its radius from R to 2R, then the ratio of the radiant energy received on earth to what it was previously will be

Which of the following statements is correct for any thermodynamic system ?

Two thermally insulated vessels 1 and 2 are filled with air at temperatures (T₁ ,T₂ ), volume (V₁ ,V₂) and pressure ( P₁ ,P₂) respectively. If the valve joining the two vessels is opened, the temperature inside the vessel at equilibrium will be

The temperature of the two outer surfaces of a composite slab, consisting of two materials having coefficients of thermal conductivity K and 2K and thickness x and 4x, respectively, are T₂ and T₁ (T₂ >T₁) . The rate of heat transfer through the slab, in a steady state is with f equal to 

Which of the following is incorrect regarding the first law of thermodynamics?

The figure shows a system of two concentric spheres of radii r₁ and r₂ are kept at temperatures T₁ and T₂, respectively. The radial rate of flow of heat in a substance between the two concentric spheres is proportional to  

A system goes from A to B via two processes I and II as shown in figure. If ΔU₁ and ΔU₂ are the changes in internal energies in the processes I and II respectively, then 

The temperature-entropy diagram of a reversible engine cycle is given in the figure. Its efficiency is 

A gaseous mixture consists of 16 g of helium and 16 g of oxygen. The ratio C_p/C_v  of the mixture is

Assuming the Sun to be a spherical body of radius R at a temperature of TK, evaluate the total radiant powerd incident of Earth at a distance r from the Sun

where r₀ is the radius of the Earth and σ is Stefan's constant.

Two rigid boxes containing different ideal gases are placed on a table. Box A contains one mole of nitrogen at temperature T₀, while Box contains one mole of helium at temperature   . The boxes are then put into thermal contact with each other, and heat flows between them until the gases reach a common final temperature (ignore the heat capacity of boxes). Then, the final temperature of the gases, T_f in terms of T₀ is

The work of 146 kJ is performed in order to compress one kilo mole of gas adiabatically and in this process the temperature of the gas increases by 7°C. The gas is (R = 8.3 J mol^–1 K^–1)

When a system is taken from state i to state f along the path iaf, it is found that Q =50 cal and W = 20 cal. Along the path ibf Q = 36 cal. W along the path ibf is