Electricity, Circuits and Magnets

Series circuits

only has one loop, which means the electrons have to flow around one path

In series circuits potential difference is?

energy shared between the components, so voltage of all components should add up to the voltage of the cell or battery

In series circuits current is?

remains the same everywhere in a series circuit

Parallel circuits

have two or more loops, which means the electrons have more than one path to flow around

In parallel circuits potential difference is?

the same across each component or branch and equals the total voltage supplied by the source

In parallel circuits current is?

the total current from the source divides among multiple branches, with the sum of individual branch currents equaling the total current

Static electricity

the build-up of electric charge on an object, which cannot easily flow away from the insulator

Electrons added or removed to an item in static electricity by?

friction

Current

the flow of electric charge around a circuit, measure of how many electrons flow past a point in a second

Current is measured in?

amperes (amps (A))VoltsVol

Current is measured with?

ammeter

Symbol for current is?

I

Equation for current?

current I (A) = charge Q (c) / time t (s)

Potential difference

the measure of how much energy the electrons have before and after a component in a circuit- energy is needed to push the electrons and generate a current, and the potential difference is what provides the push for the electrons to move around the circuit

Potential difference is measured in?

volts (V)

Potential difference is measured with?

voltmeter

Connected in parallel?

voltmeter

Connected in series?

ammeter

Resistance

a measure of how difficult it is ti pass on electric current through a conductor

Resistance is measured in?

ohms (Ω)

Symbol for potential difference?

V

Resistance is measured using?

ohmmeter

Equation for potential difference?

potential difference V (V) = resistance R (Ω) x current I (A)

Equation for resistance?

resistance R (Ω) = potential difference V (V) / current I (A)

Cell

provides electrical energy to circuit

Battery

multiple cells

Lamp

converts electrical energy into light

Resistor

restricts the flow of electrical current a particular component

Switch

can break or connect the circuit so the current flows

Variable resistor

used to control current

Light dependent resistor

converts light to electrical resistance

Fuse

breaks a circuit when current exceeds safe levels

LED

semiconductor that converts electrical energy into light

Magnetism

is an invisible force exerted by magnets

Like poles?

repel

Opposite poles?

attract

The three main magnetic metals?

iron (Fe), nickel (Ni) and cobalt (Co)

The earth has a magnetic inner core made of?

iron

Electromagnets

are non-permanent magnets that can be made magnetic by wrapping coil of insulated wire around it and connecting the wire to an energy source

Iron core- electromagnet

becomes magnetised when in the wire’s magnetic field

Coil of insulated wire- electromagnet

carries the current around the core creating a magnetic field

Cell- electromagnet

provides the voltage pushing the current through the wire

Switch- electromagnet

allows current to be turned on and off

The electromagnet can be made stronger by?

1. making the core iron

2. adding more turns on the coil

3. increasing current

4. larger turns

The electromagnet can be made weaker by?

1. removing iron core

2. adding less turns on the coil

3. decreasing current

4. larger turns

How does a circuit breaker with an electromagnet work?

1. there is a problem with the circuit and the current increases

2. magnetic field created by electromagnet increases

3. force pulling on the iron core increases

4. magnetic force overcomes the force provided by the spring

5. bolt accelerates towards the electromagnet

6. toggle is pushed upwards by the spring-loaded switch

How does a bell with an electromagnet work?

1. the switch is closed

2. current starts to flow

3. electromagnet creates a magnetic field

4. soft iron is attracted towards the electromagnet

5. springy metal moves and clanger hits the bell'

6. springy metal comes away from contact

7. the circuit is broken and the current stops flowing

8. magnetic field around the iron core disappears

9. springy metal springs back to original position

How does a speaker work?

1. when the current is switched on, the electromagnet will develop a north and south pole

2. the current keeps switching direction, and either be attracted or repelled from the magnet

3. the force will cause the cone to move back a forth, creating sound waves (which are mechanical waves)

How do you change pitch in a speaker?

change the frequency of the electricity signal so the sound waves are produced more quickly or slowly

How do you change volume in a speaker?

change the strength of the current so the amplitude of the waves is bigger and the sound gets louder