ISC 2024 Electricity and Electronics Question Paper for Class 12

About this paper

This is the ISC Class 12 Electricity and Electronics paper from the 2024 board examination, code 1224-866. It carries 80 marks and lasts three hours, with an extra fifteen minutes for reading only. All thirteen questions are compulsory. Section A is a sixteen-mark set of very short items: multiple-choice questions, one-word answers, a matching exercise and true-or-false statements. Section B has eight four-mark questions, with an internal choice in two of them, on single-phase motors, regulated supplies, the triode, rectifiers and the cathode-ray oscilloscope. Section C has four eight-mark questions on power distribution, transistor amplifiers, d.c. generators and motors, and semiconductors, and Question 12 offers an internal choice. This copy has the questions only.

Exam

ISC Class 12

Subject

Electricity and Electronics

Year

2024

Paper code

1224-866

Maximum marks

80

Time allowed

3 hours + 15 min reading

Questions

13

Pages

7

Answers included

No, questions only

Paper pattern

• Section A

  16 marks

  Question 1: multiple-choice items, short completions, a matching exercise and true-or-false statements

• Section B

  32 marks

  Questions 2–9, four marks each; internal choice in two questions

• Section C

  32 marks

  Questions 10–13, eight marks each; internal choice in Question 12

Topics covered

• Cathode ray oscilloscope
• DC generators
• Single-phase induction motors
• Transistor amplifiers
• Zener diode and voltage regulation
• Rectifiers
• DC motors and back emf
• Domestic wiring and fuses
• Transducers and microphones
• Semiconductor diodes
• Triode valve

Questions from this paper

1. Name the two types of single-phase motors that are made to function as self-start machines, and briefly explain any one of them.
2. Draw a neat and labelled diagram of a full-wave rectifier.
3. Write the function of the armature windings, poles, commutator and brushes of a generator.
4. Explain the process of distribution of electric power to houses, and the importance of a fuse and a trip in an electric circuit.
5. Differentiate between common-emitter and common-base amplifiers on the basis of current gain, power gain and phase shift.
6. Explain the significance of back emf in a d.c. motor, and why a series motor develops a high starting torque.