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JEE Main 2021 (Online) 25th July Morning Shift
+4
-1
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 the expansion respectively, then the value of $${{{T_1}} \over {{T_2}}}$$ will be :
A
$${\left( {{{{l_1}} \over {{l_2}}}} \right)^{{2 \over 3}}}$$
B
$${\left( {{{{l_2}} \over {{l_1}}}} \right)^{{2 \over 3}}}$$
C
$${{{l_2}} \over {{l_1}}}$$
D
$${{{l_1}} \over {{l_2}}}$$
2
JEE Main 2021 (Online) 25th July Morning Shift
+4
-1
Two different metal bodies A and B of equal mass are heated at a uniform rate under similar conditions. The variation of temperature of the bodies is graphically represented as shown in the figure. The ratio of specific heat capacities is :

A
$${8 \over 3}$$
B
$${3 \over 8}$$
C
$${3 \over 4}$$
D
$${4 \over 3}$$
3
JEE Main 2021 (Online) 22th July Evening Shift
+4
-1
What will be the average value of energy for a monoatomic gas in thermal equilibrium at temperature T?
A
$${3 \over 2}{k_B}T$$
B
$${k_B}T$$
C
$${2 \over 3}{k_B}T$$
D
$${1 \over 2}{k_B}T$$
4
JEE Main 2021 (Online) 20th July Evening Shift