Current Electricity (9)

Question 0

Wires are drawn as _____ lines

Answer 0

Straight lines

Question 1

Components shoud NOT be positioned at _______

Answer 1

Corners

Question 2

What is current

Answer 2

The flow of NEGATIVE charges around a circuit

Question 3

What is current measured in? And what is the symbol?

Answer 3

Amps (A)

Question 4

Does current flow from negative to positive or positive to negative

Answer 4

Positive to negative

Question 5

Does current flow through the easiest route?

Answer 5

Yes

Question 6

What instrument is used to measure current?

Answer 6

An ammeter

Question 7

What can you say about the size of the current at any point in a series circuit?

Answer 7

It always stays the same

Question 8

How do currents behave at a junction in a parallel circuit?

Answer 8

The current splits up. More of it will go down the easier route but it always has to split if there is a route it can take.

Question 9

What does resistance do to current?

Answer 9

It slows it down

Question 10

More resistance means…

Answer 10

It is harder for current to get through

Question 11

What is a short circuit?

Answer 11

When the current can take a path of lower resistance to flow around its original circuit.

Question 12

More components create more ___________

Answer 12

Resistance

Question 13

Give 3 benefits of parallel circuits.

Answer 13

• You can switch them off individually.
• Lamps remain the same brightness.
• If one lamp breaks then then the others still work

Question 14

What is energy measured in and what is the symbol for it.

Answer 14

Joules (J)

Question 15

What is voltage measured in and what is the symbol for it.

Answer 15

Volts (V)

Question 16

What is resistance measured in and what is the symbol for it?

Answer 16

Ohms

Just imagine the symbol

Question 17

2 problems with series circuits.

Answer 17

• If one bulb breaks then none of them work.

* Bulbs go dimmer when more are added.

Question 18

How do you work out the resistance of a particular component.

Answer 18

You measure the current through the component, using an ammeter

Question 19

More bulbs = ______ resistance = _______ current

Answer 19

More bulbs = more resistance = less current

Question 20

Fewer bulbs = ______ resistance = _______ current

Answer 20

Fewer bulbs = less resistance = more current

Question 21

An electric current flowing in a circuit can produce three energy changes in the circuit:

Answer 21

Chemical
Electrical
Light

Question 22

How do you measure the resistance of a resistor using the 3 colours

Answer 22

Colours = numbers
First colour = first number
Second colour = second number
Third colour = indicates the number of zeros

Question 23

What does a resistor do

Answer 23

Prevents too much current going through an appliance

Question 24

Why do we use resistors

Answer 24

They protect devices

Question 25

What is a variable resistor

Answer 25

A device that somebody can manually change the resistance of

Question 26

Example of a variable resistor

Answer 26

``` Volume control Dimmer switch (lighting) ```

Question 27

What does a thermistor do

Answer 27

As temperature increases resistance decreases (negative correlation)

Question 28

What does an LDR do

Answer 28

As light levels increase resistance decreases

Question 29

Where is a thermistor used

Answer 29

In a thermostat

Question 30

Where is an LDR used

Answer 30

Security lighting

Question 31

The current through a resistor at constant temperature is directly _______________ to the potential difference across the resistor

Answer 31

Directly proportional

Question 32

What is a ring main circuit

Answer 32

A circuit that provides a way of allowing several appliances in different parts of the same room to be connected to the mains using a minimum amount of wiring

Question 33

Ring circuits usually consist of 3 wires:

Answer 33

The live wire The neutral wire The earth wire

Question 34

For a diode, it's forward resistance is _______ and it's reverse resistance is ____________

Answer 34

Zero | Infinite

Question 35

What is the live wire

Answer 35

The wire that provides the path along which the electrical energy from the power station travel

Question 36

What is the neutral wire

Answer 36

The wire that completes the circuit

Question 37

Electrons flow easily through all ________

Answer 37

Metals

Question 38

In ______________ all the electrons are held tightly in position and are unable to move from atom to atom

Answer 38

Insulators

Question 39

What is the earth wire

Answer 39

The wire that protects you by making current flow back to the ground

Question 40

We measure electric charge (Q) in units called ___________ (__)

Answer 40

Coulombs (C)

Question 41

A voltmeter should be connected 'across' the _____________ being measured (in parallel)

Answer 41

Component

Question 42

Example of series circuit

Answer 42

Decorative lights (Christmas lights)

Question 43

As the charges flow around a circuit, the energy they carry is converted into other forms of energy by the components they pass through. The __________ across each component tells us how much energy it is _____________

Answer 43

Voltage | Converting

Question 44

Example of parallel circuit

Answer 44

Lighting in homes

Question 45

What is ohms law

Answer 45

The current that flows through a conductor is directly proportional to the potential difference across its ends, providing its temperature remains constant