Electricity: Magnetic and Heating Effects Practice Flashcards

This set of flashcards covers the magnetic and heating effects of electric current, electromagnetism, chemical cells (Voltaic and Dry cells), and battery technology based on Grade 8 Science notes.

Who discovered the connection between electricity and magnetism, and in what year?

The professor Hans Christian Oersted in $1820$.

What is the magnetic effect of electric current?

The phenomenon where electric current flowing through a conductor produces a magnetic field around it.

How is a magnetic field defined in the context of a magnet or current-carrying wire?

The region around a magnet or a current carrying wire where its magnetic effect can be felt, such as by the deflection of a compass needle.

What happens to the magnetic field of a wire when the electric current stops flowing?

The magnetic field disappears and the compass needle returns to its original direction.

What is an electromagnet?

A current carrying coil that behaves as a magnet.

What is typically added to an electromagnet to make it stronger for practical applications?

An iron core.

What three factors can be used to increase the strength of an electromagnet?

Increasing the amount of electric current, increasing the number of turns in the coil, or inserting an iron core.

How can the poles of an electromagnet be reversed?

By changing the direction of the electric current.

Why does the Earth behave like a giant magnet?

Deep inside the Earth, the movement of liquid iron in the core creates electric currents that generate a magnetic field.

What are two biological or environmental benefits of Earth's magnetic field?

It helps migratory animals navigate across oceans and acts as a shield blocking harmful particles from space.

What is the heating effect of electric current?

The process by which a conductor gets heated when an electric current passes through it due to resistance.

Why does a nichrome wire generate more heat than a copper wire of the same size?

Because nichrome offers higher resistance to the flow of current, causing more electrical energy to be converted into heat energy.

On what four factors does the amount of heat generated in a wire depend?

The material, thickness, length of the wire, and the duration for which the current flows.

What is a 'heating element' in household appliances?

A rod or a coil of wire inside appliances like electric irons or heaters that converts electrical energy into heat.

What is a common safety risk associated with the heating effect of electric current in household circuits?

Overheating may cause damage to plugs and sockets, melt plastic parts, or lead to fires.

What are the three main components of a Voltaic cell?

Two electrodes made of different materials and a liquid called an electrolyte.

In a lemon cell experiment, what components act as the electrodes and the electrolyte?

The iron nails and copper wires act as electrodes, and the lemon juice acts as the electrolyte.

What is the internal structure of a dry cell?

A zinc container acting as the negative terminal, a central carbon rod with a metal cap acting as the positive terminal, and a thick moist paste as the electrolyte.

What are solid-state batteries?

Future battery technology that replaces liquid or paste-like electrolytes with solid materials for faster charging and better safety.

Why is it important to dispose of batteries at 'e-waste' recycling facilities?

To prevent harmful materials like lead, cadmium, nickel, or lithium from causing fires or environmental damage, and to recover valuable materials for reuse.