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Important Questions

Junction Diodes — Important Questions

ICSE · Class 12 · Physics

69 important questions from Junction Diodes for ICSE Class 12 Physics, with answers. Includes multiple choice questions. Written for the board exams 2027.

69 questions42 flashcards6 formulas & key relations5 concepts

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A step-by-step diagram illustrating the formation of a p-n junction. Show a p-type and n-type semiconductor brought into contact, followed by the diffusion of majority carriers, the formation of immob
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69 Questions·
multiple choice

Important Questions from Junction Diodes

1multiple choice
3 marks

A diode has a peak input voltage of 20 V, a barrier voltage of 0.7 V, a forward resistance of 10 Ω, and a load resistance of 500 Ω. What is the peak current through the circuit?

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37.8 mA

Use V_0 = V_B + I_0(R_F + R_L). Thus I_0 = (20 - 0.7)/(10 + 500) = 19.3/510 = 0.0378 A = 37.8 mA.

2multiple choice
3 marks

A silicon diode with barrier voltage 0.7 V is connected to a 500 Ω load and carries a peak current of 37.8 mA. What is the peak voltage across the load?

Show answer

18.9 V

The load voltage is V_L = I_0R_L = 0.0378 × 500 = 18.9 V.

3multiple choice
3 marks

A Zener diode has V_Z = 12 V and is used with a load resistance of 1 kΩ. If the Zener current is nearly zero, what input voltage is needed when the series resistance is 150 Ω?

Show answer

13.8 V

Load current is I_L = V_Z/R_L = 12/1000 = 12 mA. With I_Z ≈ 0, I = 12 mA. Then V_in = IR + V_Z = 0.012 × 150 + 12 = 1.8 + 12 = 13.8 V.

4multiple choice
3 marks

A Zener regulator has V_Z = 12 V, series resistance 150 Ω, load resistance 1 kΩ, and maximum Zener current 20 mA. What is the maximum input voltage that keeps the output at 12 V?

Show answer

16.8 V

Load current is 12 mA. At maximum Zener current, total current is I = 12 + 20 = 32 mA. Then V_in = IR + V_Z = 0.032 × 150 + 12 = 4.8 + 12 = 16.8 V.

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Frequently Asked Questions

What are the important topics in Junction Diodes for ICSE Class 12 Physics?
Key topics in Junction Diodes include Formation of p-n Junction, Forward Bias and Reverse Bias, V-I Characteristics and Breakdown, Diode as a Rectifier. Study these first, then practise questions on each for the ICSE Class 12 board exam.
How many important questions are there in Junction Diodes?
Super Tutor has 69 practice questions for Junction Diodes, including multiple choice questions. A sample with answers is on this page.

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

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