In a common base transistor circuit, the current gain is 0.98. On changing the emitter current by 5.00 mA, the change in collector current is

Options

A. 0.196 mA
B. 2.45 mA
C. 4.9 mA
D. 5.1 mA

Answer

To solve the problem, we need to use the relationship between the emitter current change (ΔIe) and the collector current change (ΔIc) in a common base transistor, which is defined by the current gain (α).

### Step-by-Step Solution:

1. **Understand the relationship**: In a common base transistor, the relationship between the change in collector current (ΔIc) and the change in emitter current (ΔIe) is given by the formula:
\[ \alpha = \frac{\Delta I_c}{\Delta I_e} \]
where:
- α is the current gain (given as 0.98),
- ΔIc is the change in collector current,
- ΔIe is the change in emitter current.

2. **Identify the given values**: From the problem, we have:
- α = 0.98,
- ΔIe = 5.00 mA.

3. **Rearrange the formula to find ΔIc**: We can rearrange the formula to solve for ΔIc:
\[ \Delta I_c = \alpha \times \Delta I_e \]

4. **Substitute the known values**: Now, substitute the known values into the equation:
\[ \Delta I_c = 0.98 \times 5.00 \text{ mA} \]

5. **Calculate ΔIc**:
\[ \Delta I_c = 4.90 \text{ mA} \]

6. **Final answer**: Therefore, the change in collector current (ΔIc) is 4.90 mA.

### Conclusion:
The change in collector current when the emitter current is changed by 5.00 mA is **4.90 mA**.