Filament of a torch bulb is

Options

A. a metal case.
B. metal tip at the centre of the base.
C. two thick wires.
D. a thin wire.

Answer

### Step-by-Step Solution:

1. **Understanding the Components of a Torch Bulb:**
- A torch bulb consists of several parts, including the filament, metal case, and wires.

2. **Identifying the Filament:**
- The filament is the part of the bulb that produces light when electricity passes through it.

3. **Characteristics of the Filament:**
- The filament is made of a **thin wire**. This thin wire is crucial because it heats up quickly when electric current flows through it, causing it to emit light.

4. **Support Structure:**
- The filament is fixed to **two thick wires**. These thick wires provide the necessary support for the filament and ensure it remains in place.

5. **Connections:**
- One of the thick wires is connected to the **metal case** of the torch bulb, while the other thick wire connects to the **metal tip at the center of the base**. This setup allows the electrical circuit to be completed, enabling the torch to function.

6. **Conclusion:**
- Based on the above points, we can conclude that the filament of a torch bulb is a **thin wire**.

### Final Answer:
The filament of a torch bulb is a **thin wire**.

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