1
JEE Main 2018 (Online) 15th April Evening Slot
+4
-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 $${{{\eta _B}} \over {{\eta _A}}}$$ ?
A
$${{12} \over 7}$$
B
$${{7} \over 12}$$
C
$${{12} \over 5}$$
D
$${{5} \over 12}$$
2
JEE Main 2018 (Online) 15th April Morning Slot
+4
-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 :
A
$$420$$ $$J$$
B
$$772$$ $$J$$
C
$$2100$$ $$J$$
D
$$2520$$ $$J$$
3
JEE Main 2018 (Online) 15th April Morning Slot
+4
-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 :
A
$$300$$ $$R$$
B
$$300$$ $$R$$ $$ln$$ $$6$$
C
$$300$$ $$R$$ $$ln$$ $$2$$
D
$$300$$ $$R$$ $$ln$$ $$7$$
4
JEE Main 2017 (Online) 9th April Morning Slot
+4
-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 ?
A
$${1 \over 2}$$ nRT
B
0
C
$${3 \over 2}$$ nRT
D
$${5 \over 2}$$ nRT
JEE Main Subjects
Physics
Mechanics
Electricity
Optics
Modern Physics
Chemistry
Physical Chemistry
Inorganic Chemistry
Organic Chemistry
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Algebra
Trigonometry
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Calculus
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