Electricity and Circuits Flashcards

1
Q

What is an electric current?

A

The flow of electrical charge around a circuit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which way do electrons flow in a circuit?

A

From - to +

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which way does conventional current flow in a circuit?

A

From + to -

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In series circuit what does potential difference around the circuit have to add up to?

A

The cell voltage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does the current in the different branches of a parallel circuit have to add up to?

A

The current leaving the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How is the current split in a series circuit?

A

It’s the same all around

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

In a parallel circuit how is the voltage split?

A

It’s the same all around

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do you calculate charge?

A

Charge (C) = current (A) x time (s)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What do you measure current with?

A

An ammeter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What do you measure potential difference with?

A

A voltmeter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How do you calculate the amount of energy transferred?

A

Energy transferred (J) = charge moved (C) x potential difference (V)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is Ohm’s law?

A

Potential difference = current x resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How can the resistance of a circuit be changed?

A

Using fixed or variable resistors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens to the current as the resistance increases?

A

The current decreases, as the resistance decreases, the current increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

If there are two resistors in a series circuit, one with of a resistance of 2Ω and the other with a resistance of 4Ω what is the total resistance of the circuit?

A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does varying the value of a variable resistor allow you to do?

A

Record the current for different potential differences

17
Q

What happens to the resistance when the light intensity increases (when using a light-dependent resistor)?

A

The resistance decreases

18
Q

When using a thermistor what happens to the resistance as the temperature increases?

A

The resistance decreases

19
Q

How can unwanted thermal energy transfers be prevented?

A

By using low resistance wires

20
Q

When is electrical energy dissipated?

A

When an electrical current does work against an electrical resistance

21
Q

When is the transfer of electrical energy to thermal energy useful?

A
  • In kettles
  • Irons
  • Toasters
22
Q

What are the disadvantages of the heating effect?

A

If too much current flows through the circuit then the appliance could catch fire or the user could be burned, also in many appliances the heating effect causes energy to be wasted

23
Q

Why would too much current be flowing through an appliance’s circuit?

A

Too many appliances being used at once

24
Q

Why is energy dissipated into thermal energy?

A

When potential difference is applied across the ends of a metal, electrons flow through the metal lattice. Electrons and metal ions collide which leads to the kinetic energy of the electrons being dissipated as thermal energy

25
Q

In direct current how does the potential difference change throughout?

A

It doesn’t change, it’s constant

26
Q

In batteries what type of current is supplied?

A

D.c

27
Q

What is alternating current?

A

Current that changes direction frequently, the potential difference is constantly changing

28
Q

What type of current is supplied by mains electricity?

A

A.c

29
Q

What do earth wires and fuses do?

A
  • If the live wire comes loose, it might touch a metal part of the device’s casing, this causes a large current to heat and this melts the wire in the fuse causing the circuit to break
  • The earth wire is connected to metal casing so when a large current flows through the live wire it flows out the earth wire
  • The circuit is no longer complete so there’s no chance of an electric shock or fire
30
Q

What does the live wire do?

A

Carries the supply of current to the appliance, it has a potential difference of 230V

31
Q

What does the neutral wire do?

A

It completes the circuit with the appliance, it has a voltage of 0V

32
Q

What are the wires in a plug made from?

A

Copper but they’re covered in colour-coded insulating plastic