A transistor has a base current of 1 mA and emitter current 90 mA. The collector current will be

Options

A. 90 mA
B. 1 mA
C. 89 mA
D. 91 mA

Explanation

To find the collector current (Ic) in a transistor, we can use the relationship between the emitter current (Ie), base current (Ib), and collector current (Ic). The relationship is given by the equation:

\[ I_e = I_c + I_b \]

Where:
- \( I_e \) is the emitter current
- \( I_c \) is the collector current
- \( I_b \) is the base current

### Step-by-step Solution:

1. **Identify the given values**:
- Base current, \( I_b = 1 \, \text{mA} \)
- Emitter current, \( I_e = 90 \, \text{mA} \)

2. **Use the relationship between the currents**:
- According to the formula, we can rearrange it to find the collector current:
\[ I_c = I_e - I_b \]

3. **Substitute the known values into the equation**:
\[ I_c = 90 \, \text{mA} - 1 \, \text{mA} \]

4. **Calculate the collector current**:
\[ I_c = 89 \, \text{mA} \]

### Final Answer:
The collector current \( I_c \) is **89 mA**.

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