A gas mixture consists of 2 moles of O₂ and 4 moles of Ar at temperature T. Neglecting all vibrational modes, the internal energy system is

A Carnot engine having an efficiency of 1 /10 as heat engine, is used as a refrigerator. If the work done on the system is 10 J, the amount of energy absorbed from the reservoir at lower temperature is

A black body is at a temperature of 5760 K. The energy of radiation emitted by the body at wavelength 250 nm is U₁, at wavelength 500 nm is U₂ and that at 1000 nm is U_3. Wien's constant, b = 2.88 × 10⁶ nmK. Which of the following is correct ?

A gas is compressed isothermally to half its initially volume. The same gas is compressed separately through an adiabatic process until its volume is again reduced to half. Then

A piece of ice falls from a height h so that it melts completely.Only one - quarter of the heat produced is absorbed by the ice and all energy of ice gets converted into heat during its fall. The value of h is [Latent heat of ice is 3.4 × 10⁵ J/kg and g = 10 N/kg]

A refrigerator works between 4°C and 30°C it is required to remove 600 calories of heat every second on order to keep the temperature of the refrigerated space constant. The power required is

(Take,1 cal - 4.2 Joules)

Two identical bodies are made of a material for which the heat capacity increases with temperature. One of these is at 100°C,while the other one is at 0°C.If the two bodies are brought into contact, then assuming no heat loss, the final common temperature is

A body cools from a temperature 3T to 2T in 10 minutes. The room temperature is T. Assume that Newton's law of cooling is applicable. The temperature of the body at the end of next 10 minutes will be

One mole of an ideal monatomic gas undergoes a process described by the equation pV3 = constant. The heat capacity of the gas during this process is

The temperature inside a refrigerator is t₂°C and the room is t₁°C. The amount of heat delivered to the room for each joule of electrical energy consumed ideally will be

A given sample of an ideal gas occupied a volume V at a pressure p and absolute temperature T . The mass of each molecule of the gas is m. Which of the following gives the density of the gas?

On observing light from three different stars P,Q and R, it was found that intensity of violet colour is maximum in the spectrum of P, the intensity of green colour is maximum in the spectrum R and the intensity of red colour is maximum in the spectrum of Q. If T_P,T_Q and T_R are the respective absolute temperatures of P,Q and R, then it concluded from the above observation that

The two ends of a metal rod are maintained at temperature 100°C and 110°C. The rate of heat flow in the rod is found to be 4.0 J/s. If the ends are maintained at temperature 200°C and 210°C, the rate of heat flow will be

Figure shows two paths that may be taken by a gas to go from a state A to a state C. In process AB,400 J of heat is added to the system and in process BC 100 J of heat is added to the system. The heat absorbed by the system in the process AC will be

A carnot engine, having an efficiency of η = 1 /10 as heat engine,is used as refrigerator. If the work done on the system is 10 J , the amount of energy absorbed from the reservoir at lower temperature is

One mole of an ideal diatomic gas undergoes a transition from A to B along a path AB as shown in the figure. The change in internal energy of the gas during the transition is

The ratio of the specific heats C_p / C_v = Ƴ in terms of degrees of freedom (n) is given by

An ideal gas is compressed to half its initial volume by means of several process.Which of the process results in the maximum work done on the gas?

4.0 g of a gas occupies 22.4 L at NTP. The specific heat capacity of the gas at constant volume is 5.0 JK^-1 mol^-1. If the speed of sound in this gas at NTP is 952 ms^-1, then the heat capacity at constant pressure is

(Take gas constant R = 8.3 JK^-1 mol^-1)

The coefficient of performance of a refrigerator of a refrigerator is 5.If the temperature inside freezer is -20°C,the temperature of the surroundings to which it rejects heat is

Two vessels contain two ideal gases A and B at the same temperature,the pressure of A being twice that of B. Under such conditions, the density of A is found to be 1.5 times the density of B. The ratio of molecular weight of A and B is

The value of coefficient of volume expansion of glycerin is 5 × 10^-4 K^-1. The fractional change in the density ofglycerin for a rise of 40°C in its temperature is

Steam at 100°C is passed into 20 g of water at 10°C. when water acquires a temperature of 80°C , the mass of water present will be [Take specific heat if water =1 cal g^-1°C^-1 and latent heat of steam = 540 cal g^-1]

Certain quantity of water cools from 70°C to 60 °C in the first 5 min and to 54 °C in the next 5 min. The temperature of the surroundings is

A monoatomic gas at a pressure p, having a volume V expands isothermally to a volume 2 V and then adiabatically to a volume 16 V. The final pressure of the gas is (take Ƴ = 5/3)

A thermodynamic system undergoes cyclic process ABCDA as shown in figure. The work done by the system in the cycle is

The mean free path of molecules of gas (radius r) is inversely proportional to

The molar specific heats of an ideal gas at constant pressure and volume are denoted by Cp and Cv respectively. If Ƴ = Cp / Cv and R is the universal gas constant, then Cv is equal to

A piece of iron is heated in a flame. If first becomes dull red then becomes reddish yellow and finally turns to white hot. The correct explanation for the above observation is possible by using

A gas is taken through the cycle A→B→C→A, as shown. What is the net work done by the gas/

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

In the given (V -T) diagram, what is the relation between pressures p₁ and p₂ ?

The amount of heat energy required to raise the temperature of 1 g of helium at NTP, from T₁K to T₂K is

A thermodynamic system is taken through the cycle ABCD as shown in figure. Heat rejected by the gas during the cycle is

If the radius of a star is R and it acts as a black body, what would be the temperature of the star, in which the rate of energy production is Q?

(σ stands for Stefan's constant)

One mole of an ideal gas goes from an initial state A to final state B via two processes. It first undergoes isothermal expansion from volume V to 3V and then its volume is reduced from 3V to V at constant pressure. The correct p -V diagram representing the two processes is

Liquid oxygen at 50 K is heated at 300 K at constant pressure of 1 atm. The rate of heating is constant. Which one of the following graphs represents the variation of temperature with time ?

When 1 kg of ice at 0°C melts to water at 0°C, the rsulting change in its entropy, taking latent heat of ice to be 80 cal /°C, is

During an isothermal expansion,a confined ideal gas does -150 J of work against its surroundings. This implies that

If ΔU and ΔW represents the increase in internal energy and work done by the system respectively in a thermodynamical process, which of the following is true?

A cylindrical metallic rod in thermal contact with two reservoirs of heat at its two ends conducts an amount of heat Q in time t. The metallic rod is melted and the material is formed into a rod of the radius of the original rod. What is the amount of heat conducted by the new rod when placed in thermal contact with the two reservoirs in time?

A black body at 227°C radiates heat at the rate of 7 cal cm^-2 s^-1. At a temperature of 727°C, the rate of heat radiated in the same units will be

In thermodynamic processes which of the following statements is not true ?

The two ends of a rod of length L and a uniform cross - sectional area A are kept at two temperatures T₁ and T₂ (T₁ > T₂). The rate of heat transfer, dQ /dt, through the rod in a steady state is given by

The internal energy change in a system that has absorbed 2kcal of heat and done 500 J of work is

At 10°C the value of the density of a fixed mass of an ideal gas divided by its pressure is x.At 110°C this ratio is

If Q,E and W denote respectively the heat added, change in internal energy and the work done in a closed cycle process, then

On a new scale of temperature (which is linear) and called the W scale, the freezing and boiling points of water are 39°W and 239°W respectively. What will be the temperature on the new scale, corresponding to a temperature of 39°C on the celsius scale ?

An engine has an efficiency of 1/6 When the Temperature of the sink is reduced by 62°C, its efficieny is doubled. Temperature of the source is