Test: Thermodynamics Level - 4 - Mechanical Engineering MCQ

Select the Kelvin-Plank statement of the second law:

According to the Clausiu’s statement of the second law:
1. heat flows from cold surface to hot surface, unaided.
2. heat flows from hot surface to cold surface, unaided.
3. heat can flow from cold surface to hot surface with the aid of external work.
Which of the above statement is /are correct ?

The more effective way of increasing the efficiency of a carnot engine is to

Consider the following statements:
1. It is the second law of thermodynamics which provides criterion as to the probability of various processes.
2. Heat and work are completely interchangeable forms of energy.
3. Work is high grade energy.
4. The complete conversion of low grade energy into high grade energy in a cycle is impossible
Which of the above statements are correct ?

The four processes of the carnot cycle are

Perpetual motion machine of second kind violates the

The efficiency of the carnot cycle may be increased by

The unit of energy in S.I. units is

An engine operates between temperature limits of 900 K and T₂ and another between T₂ and 400 K for both to be equally efficient T₂ will be equal to

For the same above engine, if work output is to be equal than T₂ will be equal to

Three engines A, B and C operating on carnot cycle respectively use air, steam and Helium as the working fluid. If all the engine operates within the same temperature limit, then which engine will have highest efficiency

If a heat engine gives an output of 3 kW when the input is 10000 J/sec then thermal efficiency of the engine will be

The pressure’of a gas in terms of its mean kinetic energy per unit volume E is equal to

Match List - I ( Laws of thermodynamics) with List -II (Defines) the following:

The slope of constant pressure line on a T-S diagram is given by

In statistical thermodynamics, entropy is defined as
1. Measure of irreversibility of a system
2. A universal property
3. Degree of randomness
4. Thermodynamic probability of disorderness
Which of the above is/are correct ?

 

Consider the following statements: In an irreversible process
1. entropy always increases
2. the sum of the entropy of all bodies taking part in a process always increases
3. Once created, entropy can not be destroyed
Which among the above is /are correct ?
 

One kg of water at room temperature is brought into contact with a high temperature thermal reservoir. The entropy change of the universe is

For a thermodynamics cycle to be irreversible, it is necessary that

In a reversible cycle, the entropy of the system

The entropy change for any closed system which undergoes an irreversible adiabatic process

Consider two subsystem 1 and 2 containing same fluid and having same mass m; but at Temperature T₁ and T₂ (T₁ > T₂) enclosed in an adiabatic enclosure separate by a partition. If the partition is removed and the fluids are allowed to mix. The entropy change of process is