Thermodynamics (NEET Physics): Questions 40 - 43 of 84

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Question number: 40

» Thermodynamics » Concept of Temperature

MCQ▾

Question

A Carnot engine whose low temperature reservoir is at 7 C has an efficiency of 50%. It is desired to increase the efficiency to 70%. By how many degrees should the temperature of the high temperature reservoir be increased?

Choices

Choice (4) Response

a.

380K

b.

280 K

c.

840K

d.

560 K

Question number: 41

» Thermodynamics » Laws of Thermodynamics » First Law of Thermodynamics

MCQ▾

Question

A system is given 200 calories of heat and it does 600 joules of work. The internal energy of the system change in this process is (J = 4.18 Joule/cal)

Choices

Choice (4) Response

a.

- 236 Joule

b.

236.5 Joule

c.

-300 Joule

d.

236 Joule

Question number: 42

» Thermodynamics » Thermal Equilibrium

MCQ▾

Question

In the diagrams (i) to (iv) of variation of volume with changing pressure is shown. A gas is taken along the path ABCD. The change in internal energy of the gas will be

graphs of volume vs pressure various patterns formed

Graphs of Volume vs Pressure Various Patterns Formed

In above figure we shows the four different, volume vs pressure graph.

Choices

Choice (4) Response

a.

Negative in cases (i), (ii) and (iii) but zero in case (iv)

b.

Positive in cases (i), (ii) and (iii) but zero in case (rv)

c.

Positive in all cases (i) to (iv)

d.

Zero in all cases

Question number: 43

» Thermodynamics » Laws of Thermodynamics » First Law of Thermodynamics

MCQ▾

Question

The specific heat of hydrogen gas at constant pressure is Cp=3.4×103calkg°C and at constant volume is Cv=2.4×10calkg°C . If one kilogram hydrogen gas is heated from 10°C to 20°C at constant pressure, the external work done on the gas to maintain it at constant pressure is

Choices

Choice (4) Response

a.

10 4 Cal

b.

5 ⨯ 10 3 Cal

c.

10 5 Cal

d.

10 3 Cal

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