JEE Main 2018 (Online) 15th April Evening Slot | Heat and Thermodynamics Question 253 | Physics

JEE Main 2018 (Online) 15th April Evening Slot

MCQ (Single Correct Answer)

-1

Two Carnot engines A and B are operated in series. Engine A receives heat from a reservoir at 600 K and rejects heat to a reservoir at temperature T. Engine B receives heat rejected by engine A and in turn rejects it to a reservoir at 100 K. If the efficiencies of the two energies A and B are represented by $${\eta _A}$$ and $${\eta _B},$$ respectively, then what is the value of $${{{\eta _B}} \over {{\eta _A}}}$$ ?

$${{12} \over 7}$$

$${{7} \over 12}$$

$${{12} \over 5}$$

$${{5} \over 12}$$

JEE Main 2018 (Online) 15th April Morning Slot

MCQ (Single Correct Answer)

-1

A Carnot's engine works as a refrigerator between $$250$$ K and $$300$$ K. It receives $$500$$ cal heat from the reservoir at the lower temperature. The amount of work done in each cycle to operate the refrigerator is :

$$420$$ $$J$$

$$772$$ $$J$$

$$2100$$ $$J$$

$$2520$$ $$J$$

JEE Main 2018 (Online) 15th April Morning Slot

MCQ (Single Correct Answer)

-1

One mole of an ideal monoatomic gas is compressed isothermally in a rigid vessel to double its pressure at room temperature, $${27^ \circ }C.$$ The work done on the gas will be :

$$300$$ $$R$$

$$300$$ $$R$$ $$ln$$ $$6$$

$$300$$ $$R$$ $$ln$$ $$2$$

$$300$$ $$R$$ $$ln$$ $$7$$

JEE Main 2017 (Online) 9th April Morning Slot

MCQ (Single Correct Answer)

-1

N moles of a diatomic gas in a cylinder are at a temperature T. Heat is supplied to the cylinder such that the temperature remains constant but n moles of the diatomic gas get converted into monoatomic gas. What is the change in the total kinetic energy of the gas ?

$${1 \over 2}$$ nRT

$${3 \over 2}$$ nRT

$${5 \over 2}$$ nRT

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