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Important Questions

Junction Transistors

ICSE · Class 12 · Physics

Most important questions from Junction Transistors for ICSE Class 12 Physics board exam 2026. MCQs, short answer, and long answer questions with marks.

53 questions35 flashcards5 concepts

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53 Questions·
multiple choicemultiple correct

Sample Questions

1multiple choice
3 marks

A common-emitter transistor has I_B = 10 microamperes and I_C = 0.50 mA. What are beta(DC) and alpha(DC) respectively?

Show answer

50 and 0.98

First, beta(DC) = I_C / I_B = 0.50 mA / 10 microamperes = 0.50 / 0.010 = 50. Then I_E = I_B + I_C = 10 microamperes + 0.50 mA = 0.510 mA. So alpha = I_C / I_E = 0.50 / 0.510 ≈ 0.98. The correct option is 50 and 0.98.

2multiple choice
3 marks

A p-n-p transistor carries 2% of emitter charge in the base. If the emitter current is 1.6 mA, what is the collector current?

Show answer

1.568 mA

If 2% is lost in the base, then 98% reaches the collector. So I_C = 0.98 × 1.6 mA = 1.568 mA. The correct option is 1.568 mA.

3multiple choice
3 marks

A common-emitter amplifier has input resistance 665 Ω and transconductance 0.1 S. What is beta(AC)?

Show answer

66.5

Use g_m = beta(AC) / R_in, so beta(AC) = g_m × R_in. Substituting values gives beta = 0.1 × 665 = 66.5. The correct option is 66.5.

4multiple choice
3 marks

A common-emitter transistor has I_B = 105 microamperes and I_C = 2.05 mA. What is beta(DC)?

Show answer

19.5

Use beta(DC) = I_C / I_B. Convert 105 microamperes to 0.105 mA. Then beta = 2.05 / 0.105 ≈ 19.5. The correct option is 19.5.

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Frequently Asked Questions

What are the important topics in Junction Transistors for ICSE Class 12 Physics?
Junction Transistors covers several key topics that are frequently asked in ICSE Class 12 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.
How to score full marks in Junction Transistors — ICSE Class 12 Physics?
Understand the core concepts first, then work through the 53 practice questions available for this chapter. Revise formulas and definitions regularly, and use flashcards for quick recall before the exam.
How many important questions are there in Junction Transistors?
There are 53 practice questions available for Junction Transistors. These cover multiple question types including MCQs, short answer, and long answer questions.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

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