Electricity: Magnetic and Heating Effects

Flashcards covering the magnetic and heating effects of electric current, electromagnetism, and various types of electric cells and batteries based on Grade 8 Science material.

Who discovered in $1820$ that electricity and magnetism are linked?

Hans Christian Oersted.

What is the phenomenon where electric current flowing through a conductor produces a magnetic field around it?

The magnetic effect of electric current.

What is the region around a magnet or current carrying wire where its magnetic effect can be felt called?

A magnetic field.

A current carrying coil that behaves as a magnet is known as what?

An electromagnet.

What material is commonly used as a core to make electromagnets stronger for practical applications?

An iron core.

Identify three ways to change the strength of an electromagnet.

(1) Changing the amount of electric current flowing through the coil, (2) changing the number of turns of the coil, or (3) both.

How can the poles of an electromagnet be reversed?

By changing the direction of the current.

Why does the Earth behave like a giant magnet?

The movement of liquid iron in the Earth's core creates electric currents, which generate a magnetic field.

What is the warming of a conductor when an electric current passes through it known as?

The heating effect of electric current.

Why is electrical energy converted into heat energy when flowing through a conductor?

The conductor faces opposition or resistance to the flow of current.

Why does a nichrome wire feel warmer than a copper wire of the same size and length when current is passed through it?

A nichrome wire offers higher resistance compared to a copper wire.

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

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

What is the name of the rod or coil of wire inside heating appliances that glows red hot?

A heating element.

What are the components of a Voltaic (or Galvanic) cell?

Two metal rods of different materials called electrodes and a liquid called an electrolyte placed in a container.

Who invented the first battery by showing that a combination of metals and liquid generated electric current?

Alessandro Volta.

In the lemon cell activity, what materials act as the electrodes and the electrolyte?

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

Why is a dry cell called 'dry'?

The electrolyte is not a liquid but a thick moist paste.

In a dry cell, what acts as the negative terminal and what acts as the positive terminal?

The zinc container acts as the negative terminal and the carbon rod acts as the positive terminal.

What is currently the most common type of rechargeable battery found in portable devices?

The lithium-ion ($Li\text{-}ion$) battery.

What are solid-state batteries?

Future batteries that replace liquid or paste-like electrolytes with solid materials to be safer, charge faster, and last longer.