Electricity

Question 1

What is current

Answer 1

Current is the flow of electrical charge.

Electrical current is the flow of electrical charge round

Question 2

How do you work our charge?

Answer 2

Charge = current x time

Question 3

What are current, time and charge measured in?

Answer 3

Current=Amps
Charge=coulombs
Time=seconds

Question 4

What is the formula linking Potential difference and resistance?

Answer 4

Potential different=current x resistance

Question 5

What is an ohmic conductor?

Answer 5

Ohmic conductors have a constant resistance and it doesn’t change with the current. The current in one is directly proportional to the potential difference.

Question 6

Parts of a circuit

Answer 6

Ammeter: measures the current in amps flowing through

Voltmeter: measures the potential difference across the circuit
Must always be placed in parallel yo what your investigating

Cell: the battery in the circuit

Question 7

Resistance - how do you change it?

Answer 7

The resistance of a circuit can depend on a number of factors like if it is series or parallel
If it’s a long or short circuit
And if the circuit contains resistors

Question 8

What is an LDR?

Answer 8

A light dependent resistor is a resistor that depends on the intensity of light. With no light the resistance is the highest.
They are used in
-automatic lights 
-solar lights 
-burglar alarms

Question 9

What is a thermistor

Answer 9

A thermistor is a temperature dependant resistor that in hot conditions the resistance drops and in cold conditions increases.
They are used in
-temperature dectectors
-car engines

Question 10

Series circuits

What are the key features

Answer 10

• different components in a line, end to end
• if you remove a component the circuit won’t work as the current can’t travel around
• the potential different is shared and adds up across the circuit

Question 11

Parallel circuits

What are the key features?

Answer 11

• Each component is separately connected to the supply
• If you remove a component the circuit still works
• they are normally used in houses for lights and other electrics
• the potential difference is the same across all components

Question 12

Mains supply

Answer 12

• is alternating current
• the frequency is 50 cycles per second
• is 230 volts

Question 13

Plugs 
Which is which
Blue 
Green 
Brown

Answer 13

Blue - neutral
Brown - live
Green -earth