In which of these circuits will the bulb glow?

Options

A.
B.
C.
D.

Answer

To determine in which of the given circuits the bulb will glow, we need to analyze the solutions provided and identify whether they can conduct electricity. The bulb will glow only if the circuit is complete and electricity is flowing through it.

### Step-by-Step Solution:

1. **Understanding the Concept of Conductivity**:
- A solution must contain ions (cations and anions) to conduct electricity. These ions are responsible for the flow of electric current.

2. **Analyzing Each Solution**:
- **Mustard Oil**:
- Mustard oil is a non-polar substance and does not dissociate into ions in solution. Therefore, it cannot conduct electricity.
- **Conclusion**: The bulb will not glow in this circuit.

- **Acetone**:
- Acetone (CH3COCH3) is a simple organic compound that does not have ions. It does not dissociate into cations and anions in solution.
- **Conclusion**: The bulb will not glow in this circuit.

- **Kerosene**:
- Kerosene is also a non-polar liquid and does not contain ions. It does not conduct electricity.
- **Conclusion**: The bulb will not glow in this circuit.

- **Copper Sulfate Solution**:
- Copper sulfate (CuSO4) dissociates in water into Cu²⁺ (cations) and SO₄²⁻ (anions). This means it has charged particles that can move and carry electric current.
- **Conclusion**: The bulb will glow in this circuit.

3. **Final Answer**:
- The only solution that allows the bulb to glow is the **Copper Sulfate Solution** (option 4).

### Summary:
- The bulb will glow only in the circuit with **Copper Sulfate Solution** because it is the only electrolyte among the given options that can conduct electricity.