If `l_(1),l_(2),l_(3)` are the lengths of the emitter, base and collector of a transistor then

Options

A. `l_(1)=l_(2)=l_(3)`
B. `l_(3) lt l_(1) lt l_(2)`
C. `l_(3) gt l_(1) gt l_(2)`
D. `l_(3) lt l_(2) lt l_(1)`

Answer

To solve the question regarding the lengths of the emitter, base, and collector of a transistor, we will analyze the structure of a transistor and the relationships between these lengths.

### Step-by-Step Solution:

1. **Understanding the Transistor Structure**:
- A transistor consists of three regions: the emitter, the base, and the collector.
- The emitter is the region that injects charge carriers (electrons or holes), the base is the thin region that allows carriers to pass through, and the collector collects the carriers.

2. **Identifying the Lengths**:
- Let \( L_1 \) be the length of the emitter.
- Let \( L_2 \) be the length of the base.
- Let \( L_3 \) be the length of the collector.

3. **Comparing the Lengths**:
- The emitter is typically designed to be longer than the base because it needs to inject a sufficient number of charge carriers.
- The base is usually the shortest region because it is thin to allow for efficient carrier transport.
- The collector is generally longer than the base but can be longer than the emitter depending on the design.

4. **Establishing Relationships**:
- From the above understanding, we can establish the following relationships:
- \( L_3 \) (collector) is greater than \( L_1 \) (emitter) because the collector must collect the carriers effectively.
- \( L_1 \) (emitter) is greater than \( L_2 \) (base) because the base is designed to be thin.
- Thus, we can conclude that \( L_3 > L_1 > L_2 \).

5. **Final Conclusion**:
- The correct relationship among the lengths is \( L_3 > L_1 > L_2 \).
- Therefore, the correct option is that \( L_3 \) is greater than \( L_1 \) which is greater than \( L_2 \).

### Answer:
The correct option is: \( L_3 > L_1 > L_2 \).

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