Thermal Properties of Matter Physics - Thermal Properties of Matter

• A
  A system $X$ is in thermal equilibrium with $Y$ but not with $Z.$ System $Y$ and $Z$ may be in thermal equilibrium with each other.
• B
  A system $X$ is in thermal equilibrium with $Y$ but not with $Z$. 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 system $Y$ and $Z$ may be in thermal equilibrium with each other.
• ✓
  Both $B$ and $C$

Answer: D.

• ✓
  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 of 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.

Answer: A.

• A
  Its speed of rotation increases.
• ✓
  Its speed of rotation decreases.
• C
  Its speed of rotation remains same.
• D
  Its speed increases because its moment of inertia increases.

Answer: B.

• A
  $2\pi\text{R }\alpha\ \Delta\text{T}$
• B
  $\pi\text{R}^2\alpha\ \Delta\text{T}$
• C
  $\frac{4\pi\text{R}^3\alpha\ \Delta\text{T}}{3}$
• ✓
  ${4\pi\text{R}^3\alpha\ \Delta\text{T}}$

Answer: D.

Refer to the plot of temperature versus time showing the changes in the state of ice on heating $($not to scale$)$. Which of the following is correct?

1. The region $AB$ represents ice and water in thermal equilibrium.
2. At $B$ water starts boiling.
3. At $C$ all the water gets converted into steam.
4. $C$ to $D$ represents water and steam in equilibrium at boiling point.

• ✓
  $a$ and $d$
• B
  $b$ and $d$
• C
  $c$ and $d$
• D
  $b$ and $c$

Answer: A.