Electricity and Magnetism

Cover current electricity, circuits, Ohm's law and magnetic effects effectively.

Level

Exam-focused

Study Time

22 min

Exam Relevance

High

Core concepts

Current, potential difference and resistance.
Ohm's law and simple circuit calculations.
Power and energy in electrical circuits.
Magnetic effects of current and basic electromagnetism.

Quick formula set

V = IR
P = VI = I²R = V²/R
Series and parallel equivalent resistance.

Common mistakes

Interchanging series and parallel rules.
Substituting voltage/current with wrong units.

Chapter-end mini quiz

5 quick questions from the question bank.

Question 1

A fuse wire must be

conducting and of low melting pointconducting and of high melting pointinsulator and of high melting pointinsulator and of low melting point

Question 2

The potential difference between the two end terminals of an electric heater is $220$ V and the current through it is $0.5$ A. What would be the current through the heater if the potential difference across the terminals of the heater is reduced to $120$ V?

1.0 A0.5 A0.27 A0.7 A

Question 3

Two resistances of 5.0 Ω and 7.0 Ω are connected in series and the combination is connected in parallel with a resistance of 36.0 Ω. The equivalent resistance of the combination of three resistors is

24.0 Ω12.0 Ω9.0 Ω6.0 Ω

Question 4

An electric wire of resistance 50 ohm is cut into five equal wires. These wires are then connected in parallel. What is the equivalent resistance of this combination?

2 ohm10 ohm0.5 ohm5 ohm

Question 5

For an electric circuit given below, the correct combination of voltage (V) and current (I) is <img src="/uploads/img/2024_nda2_gat_72.png" alt="Circuit Diagram"/>

V = 900 V; I = 18 AV = 300 V; I = 5.5 AV = 600 V; I = 1 AV = 300 V; I = 2 A

Source Base

NCERT current electricity and magnetism chapters
CBSE circuit and Ohm's law numerical exercises

Back to Physics Chapters Previous: Light, Reflection, Refraction and Optics Next: Devices and Everyday Physics