5
MCQ (Single Correct Answer)
As the temperature is increased, the period of a pendulum
A
increases as its effective length increases even though its centre of mass still remains at the centre of the bob
B
decreases as its effective length increases even though its centre of mass still remains at the centre of the bob
C
increases as its effective length increases due to shifting to centre of mass below the centre of the bob
D
decreases as its effective length remains same but the centre of mass shifts above the centre of the bob
6
MCQ (Single Correct Answer)
Heat is associated with
A
kinetic energy of random motion of molecules
B
kinetic energy of orderly motion of molecules
C
total kinetic energy of random and orderly motion of molecules
D
kinetic energy of random motion in some cases and kinetic energy of orderly motion in other
7
MCQ (Single Correct Answer)
The radius of a metal sphere at room temperature $T$ is $R$ and the coefficient of linear expansion of the metal is $\alpha$. The sphere heated a little by a temperature $\Delta T$ so that its new temperature is $T+\Delta T$. The increase in the volume of the sphere is approximately.
A
$2 \pi R \alpha \Delta T$
B
$\pi R^2 \alpha \Delta T$
C
$4 \pi R^3 \alpha \Delta T / 3$
D
$4 \pi R^3 \alpha \Delta T$
8
MCQ (Single Correct Answer)
A sphere, a cube and a thin circular plate, all of same material and same mass are initially heated to same high temperature.
A
Plate will cool fastest and cube the slowest
B
Sphere will cool fastest and cube the slowest
C
Plate will cool fastest and sphere the slowest
D
Cube will cool fastest and plate the slowest
9
MCQ (Multiple Correct Answer)
Mark the correct options
A
A system $X$ is in thermal equilibrium with $Y$ but not with $Z$. The systems $Y$ and $Z$ may be in thermal equilibrium with each other.
B
A system $X$ is in thermal equilibrium with $Y$ but not with $Z$. The systems $Y$ and $Z$ are not in thermal equilibrium with each other.
C
A system $X$ is neither in thermal equilibrium with $Y$ nor with $Z$. The systems $Y$ and $Z$ must be in thermal equilibrium with each other.
D
A system $X$ is neither in thermal equilibrium with $Y$ nor with $Z$. The systems $Y$ and $Z$ may be in thermal equilibrium with each other.