Electromagnetism
Current Electricity
MCQ (Single Correct Answer)
Moving Charges and Magnetism
MCQ (Single Correct Answer)
Magnetism and Matter
MCQ (Single Correct Answer)
Electromagnetic Induction
MCQ (Single Correct Answer)
Alternating Current
MCQ (Single Correct Answer)
Electromagnetic Waves
MCQ (Single Correct Answer)
Modern Physics
Dual Nature of Radiation
MCQ (Single Correct Answer)
Semiconductor Devices and Logic Gates
MCQ (Single Correct Answer)
Communication Systems
MCQ (Single Correct Answer)
1
COMEDK 2023 Morning Shift
MCQ (Single Correct Answer)
+1
-0

An ideal gas goes from state $$A$$ to state $$B$$ via three different processes as indicated in the $$p$$-$$V$$ diagram. If $$Q_1, Q_2$$ and $$Q_3$$ indicate the heat absorbed by the three processes and $$\Delta U_1, \Delta U_2$$ and $$\Delta U_3$$ indicate the change in internal energy along the three processes respectively, then

COMEDK 2023 Morning Shift Physics - Heat and Thermodynamics Question 18 English

A
$$Q_1 > Q_2 > Q_3$$ and $$\Delta U_1=\Delta U_2=\Delta U_3$$
B
$$Q_3 > Q_2 > Q_1$$ and $$\Delta U_1=\Delta U_2=\Delta U_3$$
C
$$Q_1=Q_2=Q_3$$ and $$\Delta U_1 > \Delta U_2 > \Delta U_3$$
D
$$Q_3 > Q_2 > Q_1$$ and $$\Delta U_1 > \Delta U_2 > \Delta U_3$$
2
COMEDK 2023 Morning Shift
MCQ (Single Correct Answer)
+1
-0

If $$150 \mathrm{~J}$$ of heat is added to a system and the work done by the system is $$110 \mathrm{~J}$$, then change in internal energy will be

A
40 J
B
110 J
C
150 J
D
260 J
3
COMEDK 2023 Morning Shift
MCQ (Single Correct Answer)
+1
-0

Two slabs are of the thicknesses $$d_1$$ and $$d_2$$. Their thermal conductivities are $$K_1$$ and $$K_2$$, respectively. They are in series. The free ends of the combination of these two slabs are kept at temperatures $$\theta_1$$ and $$\theta_2$$. Assume $$\theta_1 > \theta_2$$. The temperature $$\theta$$ of their common junction is

A
$$\frac{K_1 \theta_1+K_2 \theta_2}{\theta_1+\theta_2}$$
B
$$\frac{K_1 \theta_1 d_1+K_2 \theta_2 d_2}{K_1 d_2+K_2 d_1}$$
C
$$\frac{K_1 \theta_1 d_2+K_2 \theta_2 d_1}{K_1 d_2+K_2 d_1}$$
D
$$\frac{K_1 \theta_1+K_2 \theta_2}{K_1+K_2}$$
4
COMEDK 2023 Morning Shift
MCQ (Single Correct Answer)
+1
-0

A cylinder of radius $$r$$ and of thermal conductivity $$K_1$$ is surrounded by a cylindrical shell of inner radius $$r$$ and outer radius $$2 r$$ made of a material of thermal conductivity $$K_2$$. The effective thermal conductivity of the system is

A
$$\frac{1}{3}\left(K_1+2 K_2\right)$$
B
$$\frac{1}{2}\left(2 K_1+3 K_2\right)$$
C
$$\frac{1}{3}\left(3 K_2+2 K_1\right)$$
D
$$\frac{1}{4}\left(K_1+3 K_2\right)$$
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