Due to thermal expansion, with rise in temperature

Options

A. a. Metallic scale reading becomes less than the actual value
B. b. Pendulum clock becomes slow
C. c. A floating body sinks a little more
D. d. The weight of a body in a liquid increases

Answer

To solve the question regarding the effects of thermal expansion with a rise in temperature, we will analyze each option provided in the question step by step.

### Step 1: Understanding Thermal Expansion
Thermal expansion refers to the tendency of matter to change in volume in response to a change in temperature. When the temperature increases, most materials expand. This expansion can affect measurements, the behavior of pendulums, buoyancy, and weight in fluids.

### Step 2: Analyzing Each Option

#### Option A: Metallic Scale Reading
- **Statement**: "Metallic scale reading becomes less than the actual value."
- **Analysis**: When the temperature rises, the metallic scale expands. This means that the distance between the markings on the scale increases. Therefore, when measuring an object, the reading on the scale will be less than the actual length of the object.
- **Conclusion**: This statement is **correct**.

#### Option B: Pendulum Clock
- **Statement**: "Pendulum clock becomes slow."
- **Analysis**: The period of a pendulum is affected by its length. As the temperature increases, the pendulum rod expands, increasing its length. Since the period of a pendulum is proportional to the square root of its length, an increase in length results in a longer period, causing the clock to run slower.
- **Conclusion**: This statement is **correct**.

#### Option C: Floating Body
- **Statement**: "A floating body sinks a little more."
- **Analysis**: As the temperature of the liquid increases, the density of the liquid decreases, which reduces the upthrust (buoyant force) acting on the floating body. If the buoyant force decreases while the weight of the body remains constant, the body will sink further into the liquid.
- **Conclusion**: This statement is **correct**.

#### Option D: Weight of the Body in Liquid
- **Statement**: "The weight of the body in a liquid is increasing."
- **Analysis**: The apparent weight of an object submerged in a fluid is given by the actual weight minus the buoyant force. Since the buoyant force decreases with the rise in temperature (as established in Option C), the net weight of the body in the liquid will increase.
- **Conclusion**: This statement is **correct**.

### Final Conclusion
All four options (A, B, C, and D) are correct regarding the effects of thermal expansion with a rise in temperature.