Thermodynamics ...

During the adiabatic expansion of 2 moles of a gas, the internal energy was found to have decreased by 100 J. The work done by the gas in this process is

For a diatomic gas, change in internal energy for a unit change in temperature for constant pressure and constant volume is U₁ and U₂, respectively. What is the ratio of U₁ to U₂?

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

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

A polyatomic gas ( = 4/3) at pressure P is compressed to (1/8)^th of its initial volume adiabatically. The pressure will change to

Calculate the temperature, in K, at which a perfect black body radiates at the rate of 5.67 watts cm^-2, σ = 5.67 × 10^-8 watts m^-2 K^-4.

Find the actual mechanical advantage of a machine, which has a velocity ratio of 3.2 and efficiency 75%.

A heat engine takes in 900 J of heat from a high temperature reservoir and produces 300 J of work in each cycle. What is its efficiency?

If a system changes from state (P₁, V₁) to (P₂, V₂) as shown below, the work done by the system is

In the given figure, when a system is taken from state i to state f along the path iaf, it is found that heat Q absorbed by the system is 50 cal and work W done by the system is 20 cal. Along the path ibf, Q given to system is 36 cal. What is the value of work done by system along the path ibf?

Which of the following statements are incorrect regarding the first law of thermodynamics?

A. It is not applicable to any cyclic process.
B. It is a restatement of the principle of conservation of energy.
C. It introduces the concept of internal energy.
D. It introduces the concept of entropy.

N moles of a monoatomic gas are carried round the reversible rectangular cycle ABCDA as shown in the diagram. The temperature at A is T₀. What is the approximate thermodynamic efficiency of the cycle?

Directions: The following question has four choices, out of which ONLY ONE is correct.

A Carnot engine, whose sink is at 300 K, has an efficiency of 40%. By how much should the temperature of source be increased, so as to increase its efficiency by 50% of original efficiency?

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

An ideal gas heat engine operates in a Carnot's cycle between 227ºC and 127ºC. It absorbs 6 x 10⁴ J heat at high temperature. The amount of heat converted into work is

An ideal gas, after going through a series of four thermodynamic states in order, reaches the initial state again (cyclic process). The amounts (Q) and work (W) involved in these states are

Q₁ = 6,000 J, Q₂ = -5,500 J, Q₃ = -3,000 J and Q₄ = 3,500 J
W₁ = 2,500 J, W₂ = -1,000 J, W₃ = -1,200 J and W₄ = xJ

The ratio of net work done by the gas to the total heat asorbed by the gas is η. What are the values of x and η?
(Nearly)

One gram of water at a constant pressure of 1.01 x 10⁵ Pa is converted into steam without any change of temperature. The volume of 1 gm of steam is 1671 cc and the latent heat of evaporation is 540 cal. The change in internal energy due to evaporation of 1 gm of water is

Consider the following statements (A) and (B). Read the statements and mark the correct answer.

A. First law of thermodynamics specifies the conditions under which a body can use its heat energy to produce work.
B. Second law of thermodynamics states that heat always flows from a hot body to a cold body.

Directions: Choose the correct option that suits Assertion and Reason from the given below :

(a) If both assertion and reason are true, and the reason is the correct explanation of the assertion.
(b) If both assertion and reason are true, but the reason is not the correct explanation of the assertion.
(c) If assertion is true statement but reason is false.
(d) If both assertion and reason are false statements

Assertion : The Carnot cycle is useful in understanding the performance of heat engines.
Reason : The Carnot cycle provides a way of determining the maximum possible efficiency achievable with reservoirs of given temperatures.

A Carnot engine absorbs 1000 calorie of heat from a source and rejects 800 calorie of heat to the sink per cycle.What is its thermal efficiency?

An ideal gas heat engine operates in a Carnot cycle between 227⁰C and 127⁰C. It absorbs 6 kcal at the higher temperature. The amount of heat (in kcal) converted into work is equal to:

A Carnot engine works as a refrigerator between 250 K and 300 K. If it receives 750 calories of heat from the reservoir at the lower temperature, then the amount of heat rejected at the higher temperature is

A Carnot engine operates with a source at 500 K and a sink at 375 K. The engine consumes 600 kcal of heat per cycle. The heat rejected to the sink per cycle is