Magnetic Effects of Electric Current — Part 2: Force on a conductor, AC and DC, and domestic circuits: visual lesson, CBSE Class 10 Science

Lesson

Forces, AC and safe wiring

Part 2 — a magnet pushes on a wire carrying current; the two kinds of current, DC and AC; and how the wiring in our homes is made safe.

In this lesson you will

Use Fleming’s left-hand rule to predict the direction of force on a conductor
Distinguish DC and AC, state the frequency of AC in India and give advantages of AC
Explain live, neutral and earth wires, fuses, overloading and short-circuiting

Diagram

A magnet pushes a current-carrying rod

A light aluminium rod between the poles of a magnet is displaced sideways when current flows. The force is perpendicular to both the current and the field.

Concept

What controls the force?

Table: reversing either the current or the field reverses the force; reversing both leaves it unchanged; the force is largest when the rod is perpendicular to the field and zero when it is parallel
Change	Effect on the rod
Reverse the current	Force reverses: rod moves the other way
Reverse the magnet (swap poles)	Force reverses
Reverse both	Force in the original direction
Rod perpendicular to the field	Largest force
Rod parallel to the field	No force

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