In an n-p-n circuit transistor, the collector current is 10 mA. If 80% electrons emitted reach the collector, then

Options

A. the emitter current will be 7.5 mA
B. the emitter current will be 12.5 mA
C. the base current will be 3.5 mA
D. the base current will be 1.5 mA

Explanation

To solve the problem, we need to find the emitter current and the base current in the given n-p-n transistor circuit. Here are the steps to arrive at the solution:

### Step 1: Understand the relationship between collector current (Ic), emitter current (Ie), and base current (Ib).
In a transistor, the relationship can be expressed as:
\[ I_e = I_c + I_b \]
Where:
- \( I_e \) = Emitter current
- \( I_c \) = Collector current
- \( I_b \) = Base current

### Step 2: Given data
We are provided with the following data:
- Collector current, \( I_c = 10 \, \text{mA} \)
- 80% of the electrons emitted reach the collector.

### Step 3: Calculate the emitter current (Ie)
Since 80% of the emitted electrons reach the collector, we can express this mathematically:
\[ I_c = 0.8 \times I_e \]

Rearranging this gives us:
\[ I_e = \frac{I_c}{0.8} \]

Substituting the value of \( I_c \):
\[ I_e = \frac{10 \, \text{mA}}{0.8} \]

Calculating this:
\[ I_e = 12.5 \, \text{mA} \]

### Step 4: Calculate the base current (Ib)
Now that we have the emitter current, we can find the base current using the relationship established in Step 1:
\[ I_b = I_e - I_c \]

Substituting the known values:
\[ I_b = 12.5 \, \text{mA} - 10 \, \text{mA} \]

Calculating this:
\[ I_b = 2.5 \, \text{mA} \]

### Final Results
- Emitter current \( I_e = 12.5 \, \text{mA} \)
- Base current \( I_b = 2.5 \, \text{mA} \)

### Summary
The emitter current is 12.5 mA and the base current is 2.5 mA.

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