Energy and Electricity Lecture Review

Flashcards covering energy transfer, conservation laws, static electricity, and the fundamental properties of electric circuits and currents.

How is energy defined in the lecture?

The ability to do work or cause change.

What are the four ways energy can be transferred?

i) Mechanically, ii) Electrically, iii) By Heating, and iv) By Radiation.

How is energy transferred mechanically?

A force (such as a push, pull, stretch, or squeeze) acts on an object to transfer energy to its kinetic store.

What causes an electrical transfer of energy?

When an electrical current flows due to a potential difference.

What is the difference between conduction and convection in heat transfer?

Conduction is heat transfer through direct physical contact, while convection is heat transfer through the movement of heated liquids or gases.

How is energy transmitted by radiation?

As waves, such as light, sound, or infrared.

State the Law of Conservation of Energy.

Energy can neither be created nor destroyed, but only be changed from one form to another (transferred or transformed).

What is Static Energy?

The temporary buildup of electric charge on the surface of a material.

What occurs during 'Charge Separation' in static electricity?

When two materials rub together, electrons can transfer from one to the other, making one object negatively charged and the other positively charged.

What happens during a static discharge?

When a charged person or object gets close to a conductor, electrons jump across the gap to equalize, resulting in a quick spark.

What is the difference between renewable and non-renewable energy sources?

Renewable sources are always being replenished by natural processes and will never run out, whereas non-renewable sources cannot be replenished within a lifetime and will eventually run out.

How is electricity defined?

A phenomena caused by the movement and interaction of electrons

What is the difference between power stations and electric cells as sources of electricity?

Power stations supply a lot of electricity for many appliances, while electric cells supply a little electricity and are portable and safe.

What is an electric current?

The flow of electricity through an electrical appliance.

What is the SI unit for electric current?

The ampere ($A$).

How many milliamperes ($mA$) are in $1\,A$?

$1,000\,mA$.

How must an ammeter be connected in a circuit?

It must be connected in series, with the positive side connected nearest to the positive terminal of the battery.

In which direction does electric current flow in terms of terminals?

It flows from the negative terminal to the positive terminal.

What is Voltage?

The electrical pressure that pushes electrical current through a circuit.

Define Electromotive Force (E.M.F).

The maximum electrical potential energy a source (like a battery or generator) can provide per unit of electric charge.

What is a battery in the context of electrical circuits?

Two or more cells connected together.

What are the two requirements for an electric current to flow?

There must be a source of electric energy and a closed circuit.

What is a Series Circuit?

A circuit where components are connected end to end to make a simple loop for current flow.

What happens in a series circuit if one bulb 'blows'?

It breaks the whole circuit and all the bulbs go out.

What is a Parallel Circuit?

A circuit where components are connected side by side, giving the current a choice of routes.

What happens in a parallel circuit if one bulb 'blows'?

There will still be a complete circuit to the other bulb, so it stays alight.