Question

In a transistor, when the emitter current changes by 9.85 mA, the collector current changes to 9.5 mA. Then the base current is

• A. 0.05 mA
• B. 0.85 mA
• C. 0.8 mA
• D. 0.35 mA

Hint:

In transistor circuits, the base current change is the difference between the emitter and collector current changes: \( \Delta I_B = \Delta I_E - \Delta I_C \).

Answer 1

The Correct Option is D

In a transistor, the relationship between the emitter current \( I_E \), the collector current \( I_C \), and the base current \( I_B \) is given by: \[ I_E = I_C + I_B \] When the emitter current changes by \( \Delta I_E = 9.85 \, \text{mA} \) and the collector current changes by \( \Delta I_C = 9.5 \, \text{mA} \), we can find the change in the base current \( \Delta I_B \) using the following equation: \[ \Delta I_B = \Delta I_E - \Delta I_C \] Substitute the given values: \[ \Delta I_B = 9.85 \, \text{mA} - 9.5 \, \text{mA} = 0.35 \, \text{mA} \] Thus, the base current change is \( 0.35 \, \text{mA} \). Therefore, the correct answer is option (4), \( 0.35 \, \text{mA} \).

Answer 2

Step 1: Understanding the problem
The emitter current (\(I_E\)) changes by 9.85 mA and the collector current (\(I_C\)) changes by 9.5 mA.
We need to find the base current (\(I_B\)).

Step 2: Relation between currents in a transistor
\[ I_E = I_C + I_B \]

Step 3: Calculate the base current
\[ I_B = I_E - I_C = 9.85\, \text{mA} - 9.5\, \text{mA} = 0.35\, \text{mA} \]

Step 4: Final answer
The base current is 0.35 mA.