An ideal heat engine working between temperature T1 and T2 has an efficiency η, the new efficiency if both the source and sink temperature are doubled, will be

(1) $\frac{\eta }{2}$

(2) η

(3) 2η

(4) 3η

Concept Questions :-

Heat engine and refrigerator
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

An ideal refrigerator has a freezer at a temperature of –13°C . The coefficient of performance of the engine is 5. The temperature of the air (to which heat is rejected) will be

(1) 325°C

(2) 325K

(3) 39°C

(4) 320°C

Concept Questions :-

Heat engine and refrigerator
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

An engine is supposed to operate between two reservoirs at temperature 727°C and 227°C. The maximum possible efficiency of such an engine is -

(1) 1/2

(2) 1/4

(3) 3/4

(4) 1

Concept Questions :-

Heat engine and refrigerator
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

An ideal gas heat engine operates in Carnot cycle between 227°C and 127°C. It absorbs 6 × 104 cal of heat at higher temperature. Amount of heat converted to work is -

(1) 2.4 × 104 cal

(2) 6 × 104 cal

(3) 1.2 × 104 cal

(4) 4.8 × 104 cal

Concept Questions :-

Heat engine and refrigerator
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Which of the following processes is reversible ?

(1) Transfer of heat by radiation

(2) Electrical heating of a nichrome wire

(3) Transfer of heat by conduction

(4) Isothermal compression

Concept Questions :-

Types of processes
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

When an ideal diatomic gas is heated at constant pressure, the fraction of the heat energy supplied which increases the internal energy of the gas, is -

(1) $\frac{2}{5}$

(2) $\frac{3}{5}$

(3) $\frac{3}{7}$

(4) $\frac{5}{7}$

Concept Questions :-

Molar Specific heat
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A monoatomic ideal gas, initially at temperature T1, is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature T2 by releasing the piston suddenly. If L1 and L2 are the lengths of the gas column before and after expansion respectively, then T1/ T2 is given by -

(1) ${\left(\frac{{L}_{1}}{{L}_{2}}\right)}^{2/3}$

(2) $\frac{{L}_{1}}{{L}_{2}}$

(3) $\frac{{L}_{2}}{{L}_{1}}$

(4) ${\left(\frac{{L}_{2}}{{L}_{1}}\right)}^{2/3}$

Concept Questions :-

Types of processes
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A closed hollow insulated cylinder is filled with gas at 0°C and also contains an insulated piston of negligible weight and negligible thickness at the middle point. The gas on one side of the piston is heated to 100°C. If the piston moves 5 cm, the length of the hollow cylinder is -

(1) 13.65 cm

(2) 27.3 cm

(3) 38.6 cm

(4) 64.6 cm

Concept Questions :-

Types of processes
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A mono atomic gas is supplied the heat Q very slowly keeping the pressure constant. The work done by the gas will be

(1) $\frac{2}{3}Q$

(2) $\frac{3}{5}Q$

(3) $\frac{2}{5}Q$

(4) $\frac{1}{5}Q$

Concept Questions :-

Molar Specific heat
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

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

(1) 4 RT

(2) 15 RT

(3) 9 RT

(4) 11 RT

Concept Questions :-

Basic terms