# Thermodynamics (NEET (NTA)-National Eligibility cum Entrance Test (Medical) Physics): Questions 72 - 75 of 86

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## Question number: 72

» Thermodynamics » Laws of Thermodynamics » Second Law of Thermodynamics

Assertion-Reason▾

### Assertion (Ꭺ)

It is not possible for a system, unaided by external agency to transfer heat from a body at low temperature to another body at higher temperature.

### Reason (Ꭱ)

According to Clauses statement, A process is possible whose sole result is the transfer heat from a cooled object to a hotter object.

### Choices

Choice (4) Response

a.

Both Ꭺ and Ꭱ are true but Ꭱ is NOT the correct explanation of Ꭺ

b.

Both Ꭺ and Ꭱ are true and Ꭱ is the correct explanation of Ꭺ

c.

Ꭺ is true but Ꭱ is false

d.

Both Ꭺ and Ꭱ are false

## Question number: 73

» Thermodynamics » Concept of Temperature

MCQ▾

### Question

An ideal heat engine working between temperature T and r, has an efficiency η, the new efficiency of engine if both the source and sink temperature are doubled, will be

### Choices

Choice (4) Response

a.

b.

η

c.

d.

## Question number: 74

» Thermodynamics » Thermal Equilibrium

MCQ▾

### Question

Two Carnot engines A and B are operated in succession. The first one, A receives heat from a source at r 1 = 500 and rejects to sink at T 2 K. The second engine B receives heat rejected by the first engine and rejects to another sink at r 3 =300K. If the work outputs of two engines are equal, then the value of T 2 will be

### Choices

Choice (4) Response

a.

550K

b.

400K

c.

100K

d.

700 K

## Question number: 75

» Thermodynamics » Concept of Temperature

MCQ▾

### Question

A scientist says that the efficiency of his heat engine which operates at source temperature 107°C and sink temperature 27°C is 26%, then

### Choices

Choice (4) Response

a.

Data are incomplete

b.

It is impossible

c.

It is possible but less probable

d.

It is quite probable