1
JEE Main 2023 (Online) 25th January Morning Shift
+4
-1 A Carnot engine with efficiency 50% takes heat from a source at 600 K. In order to increase the efficiency to 70%, keeping the temperature of sink same, the new temperature of the source will be :

A
300 K
B
1000 K
C
900 K
D
360 K
2
JEE Main 2023 (Online) 25th January Morning Shift
+4
-1 A bowl filled with very hot soup cools from 98$$^\circ$$C to 86$$^\circ$$C in 2 minutes when the room temperature is 22$$^\circ$$C. How long it will take to cool from 75$$^\circ$$C to 69$$^\circ$$C?

A
2 minutes
B
0.5 minute
C
1.4 minutes
D
1 minute
3
JEE Main 2023 (Online) 24th January Evening Shift
+4
-1 Let $$\gamma_1$$ be the ratio of molar specific heat at constant pressure and molar specific heat at constant volume of a monoatomic gas and $$\gamma_2$$ be the similar ratio of diatomic gas. Considering the diatomic gas molecule as a rigid rotator, the ratio, $$\frac{\gamma_1}{\gamma_2}$$ is :

A
$$\frac{35}{27}$$
B
$$\frac{25}{21}$$
C
$$\frac{21}{25}$$
D
$$\frac{27}{35}$$
4
JEE Main 2023 (Online) 24th January Evening Shift
+4
-1 In an Isothermal change, the change in pressure and volume of a gas can be represented for three different temperature; $$\mathrm{T_3 > T_2 > T_1}$$ as :

A B C D JEE Main Subjects
Physics
Mechanics
Electricity
Optics
Modern Physics
Chemistry
Physical Chemistry
Inorganic Chemistry
Organic Chemistry
Mathematics
Algebra
Trigonometry
Coordinate Geometry
Calculus
EXAM MAP
Joint Entrance Examination