If α = 0.995, IE = 10 mA and ICO = 0.5 mA, then ICEO will be  

Explanation:

Analysis of the Correct Option:

To solve this numerical problem, we need to calculate the collector-emitter leakage current (ICEO) in a transistor based on the given parameters:

• α (common base current gain) = 0.995
• IE (emitter current) = 10 mA
• ICO (collector leakage current with base open) = 0.5 mA

The relationship between ICEO, ICO, and α is given by the formula:

ICEO = ICO / (1 - α)

Step-by-Step Solution:

1. Substitute the given values into the formula:

ICEO = ICO / (1 - α)

ICEO = 0.5 mA / (1 - 0.995)

2. Calculate the denominator:

1 - α = 1 - 0.995 = 0.005

3. Perform the division:

ICEO = 0.5 mA / 0.005

ICEO = 100 mA

4. Convert the result into μA:

ICEO = 100 × 10^-3 mA

ICEO = 100 μA

Conclusion:

The collector-emitter leakage current (ICEO) is 100 μA, which matches Option 1.

Important Information

To further understand the analysis, let’s evaluate the other options:

Option 2: 25 μA

This option is incorrect because it does not match the calculated value of ICEO. If we substitute the given values into the formula, the result clearly exceeds this value. This could be a misunderstanding of the formula or an incorrect calculation.

Option 3: 10.1 μA

This option is also incorrect for the same reasons as Option 2. The calculated value of ICEO is significantly higher than 10.1 μA, indicating that this value was derived from an incorrect formula or computation.

Option 4: 10.5 μA

Similar to Options 2 and 3, this option is incorrect because the actual value of ICEO, based on the given parameters, is 100 μA. Any deviation from this value implies an error in the calculation process.

Conclusion:

Understanding the relationship between α, IE, ICO, and ICEO is crucial for analyzing transistor leakage currents. The formula ICEO = ICO / (1 - α) provides a straightforward way to calculate the collector-emitter leakage current. Using this formula correctly, we determined that the correct value of ICEO is 100 μA, confirming that Option 1 is the correct choice.