An unknown transistor needs to be identified as `npn` and `pnp` type. A multimeter, wilth `+ve` and `-ve` terminals is used to measure resistance between different terminals transistor. If terminal `2` is the base of the transistor then which of the following is correct for a `pnp` transistor?

Options

A. `+ve` terminals `3, -ve` terminal `2`, resistance high
B. `+ve` terminal `2, -ve` terminal `3`, resistance low
C. `+ve` terminal `1, -ve` terminal `2`, resistance high
D. `+ve` terminal `2,-ve` terminal `1`, resistance high

Explanation

To identify whether the unknown transistor is of type `npn` or `pnp`, we can use a multimeter to measure the resistance between its terminals. Given that terminal 2 is the base of the transistor, we will analyze the characteristics of a `pnp` transistor.

### Step-by-Step Solution:

1. **Understanding the PNP Transistor Structure:**
- A PNP transistor consists of two p-type semiconductor materials (P) and one n-type semiconductor material (N) sandwiched between them. The terminals are typically labeled as Emitter (E), Base (B), and Collector (C).

2. **Identifying the Terminals:**
- In our case, terminal 2 is the base (B). The other two terminals will be the emitter (E) and collector (C). We can label them as follows:
- Terminal 1: Emitter (P)
- Terminal 2: Base (N)
- Terminal 3: Collector (P)

3. **Forward and Reverse Bias Conditions:**
- For a PNP transistor:
- **Forward Bias:** The emitter (P) must be at a higher potential than the base (N). This means if we connect the positive terminal of the multimeter to the emitter (Terminal 1) and the negative terminal to the base (Terminal 2), we will observe low resistance.
- **Reverse Bias:** If we connect the positive terminal to the base (Terminal 2) and the negative terminal to the emitter (Terminal 1), we will observe high resistance.

4. **Using the Multimeter:**
- To determine the type of transistor, we can measure the resistance between the terminals:
- **Measure between Terminal 1 (Emitter) and Terminal 2 (Base):**
- If the multimeter shows low resistance, it indicates forward bias (which is expected for a PNP transistor).
- **Measure between Terminal 2 (Base) and Terminal 1 (Emitter):**
- If the multimeter shows high resistance, it indicates reverse bias.

5. **Conclusion:**
- Based on the measurements:
- If Terminal 1 is connected to the positive terminal of the multimeter and Terminal 2 to the negative, we expect low resistance (forward bias).
- If Terminal 2 is connected to the positive terminal and Terminal 1 to the negative, we expect high resistance (reverse bias).
- Therefore, the correct option for identifying a PNP transistor when Terminal 2 is the base is that the resistance will be high when the base is connected to the positive terminal of the multimeter and the emitter to the negative terminal.

### Final Answer:
The correct option for a PNP transistor, when Terminal 2 is the base, is that it shows high resistance when the base is connected to the positive terminal of the multimeter.