P4

Question 1

How can you charge an object?

Answer 1

Charging by friction from rubbing insulating materials together.
This is because electrons are transferred from one material to the other.
Materials which gain electrons become negatively charged
Materials which lose electrons become positively charged

Question 3

What happens when charged object meet?

Answer 3

When both positively charged they repel
When both negatively charged they repel
When opposite they attract

Question 4

How do charged objects exert forces on each other?

Answer 4

A charged object creates an electric field around itself
The electric field is strongest closest to the object

Question 5

What is a cell?

Answer 5

Provides the push for electrons in a circuit

Question 6

What is a ammeter?

Answer 6

Used to measure current

Question 7

What is a voltmeter?

Answer 7

Used to measure potential difference (voltage)

Question 8

What is a lamp?

Answer 8

Emits light when current passes through it

Question 9

What is a LDR?

Answer 9

Light dependent resistor

Question 10

what is a fuse?

Answer 10

Melts and breaks if the current is too high

Question 11

What is a resistor?

Answer 11

Limits the current in a circuit

Question 12

What is an LED?

Answer 12

Emits light when current passes through it
Light Emitting Diode

Question 13

What is a switch?

Answer 13

Enables current in a circuit to be switched on or off

Question 14

What is a thermistor?

Answer 14

Temperature dependent resistor

Question 15

What is a variable?

Answer 15

Allows current to be varied

Question 16

What is electric current?

Answer 16

The flow of charge
The charge is carried by electrons
The electrons transfer energy from a power source to the components in the circuit

Question 17

What is the equation for current?

Answer 17

Current = charge / time
I = Q/t

Question 18

What is the unit for current?

Answer 18

Amperes (amps)
1 ampere is a rate of 1 coulomb per second

Question 19

What is potential difference?

Answer 19

P.d. Is the amount of work done (energy transferred) by each coulomb of charge that passes through the circuit between two points

Question 20

What is the equation for potential difference?

Answer 20

Potential difference = energy / charge
V = E/Q

Question 21

What is electrical resistance?

Answer 21

Electrical resistance or resistance in a circuit is the opposition to the flow of charge. Measured in OHMS

Question 22

What factors affect resistance?

Answer 22

Length of wire
Thickness of wire
Material the wire is made of
Heat
Conductivity

Question 23

What is Ohms law?

Answer 23

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

Question 24

What is the equation for potential difference resistance and current?

Answer 24

Potential difference = current x resistance
V = I x R

Question 25

What is a series circuit?

Answer 25

A series circuit is when all the electrical components are wired one after another?

Question 26

What happens to the current if more components are added in series?

Answer 26

Current in a series circuit remains the same unless you add more components. The current would decrease because the resistance would increase across the components

Question 27

What is the resistance in a series circuit?

Answer 27

The total resistance in a series circuit is the sum of the resistance of each component in the circuit

Question 28

What are the circuit rules for series circuits for resistance, current, potential difference?

Answer 28

Current- the current that flows across each component in series is the same Potential difference- the total potential difference of the supply is shared between the components in series Resistance- the total resistance in a series circuit is the sum of the resistance of each component in the circuit

Question 29

What is a parallel circuit?

Answer 29

In parallel circuits components are connected in two separate loops or different branches therefore components are placed alongside different paths. Ammeters are always in series Voltmeters are always in parallel

Question 30

What happens to current in a parallel circuit?

Answer 30

The total current through the whole circuit is the sum of the currents through the separate branches

Question 31

What is the rule for potential difference in a parallel circuit?

Answer 31

For components in parallel the potential difference across each branch is the same