Electricity

Question 1

What is electrical current

Answer 1

Flow of electrical charge
Will only flow round a complete circuit if there is a potential difference

Question 2

What is the unit for current

Answer 2

Ampere

Question 3

What is the current in a series circuit

Answer 3

Equal everywhere

Question 4

What is potential difference

Answer 4

Driving force that pushes charge around

Question 5

What is the unit for potential difference

Answer 5

Volts

Question 6

What is resistance

Answer 6

Anything that slows the flow down

Question 7

What is the unit for resistance

Answer 7

Ohms

Question 8

What does a greater resistance mean

Answer 8

The smaller the current that flows for a constant potential difference

Question 9

What factors affect resistance?

Answer 9

Series or parallel circuit
Length of wires used in the circuit

Question 10

At a constant temperature what is the current directly proportional to?

Answer 10

Potential difference

Question 11

What does resistance increase with?

Answer 11

As the current increases so does the thermal energy store, which results in the resistance increasing.

Question 12

What does an ohmic conductor graph look like

Answer 12

Directly proportional (straight line)

Question 13

What does an filament lamp graph look like

Answer 13

Curved line in an ‘f’ shape

Question 14

What does an diode graph look like

Answer 14

Only positive values that is exponential (but touches 0)

Question 15

Practical for IV Characteristics

Answer 15

Set up a circuit with a battery, ammeter, filament lamp with a voltmeter in parallel and a variable resistor
Start varying the resistance and record the current and voltage when the resistance changes
Repeat each reading twice to ensure accurate results
Swap the wires attached to the battery to change the direction of the current and obtain negative results
Plot a graph

Question 16

What is an LDR?

Answer 16

Light dependant resistor
In brighter light the resistance falls and in darkness the resistance is highests

Question 17

Examples of LDRs

Answer 17

Automatic Night Lights
Outdoor lighting
Burglar detectors

Question 18

What is a thermistor

Answer 18

Temperature dependant resistor
In hot conditions the resistance falls and in cool conditions the resistance increases

Question 19

Examples of a thermistor

Answer 19

Car engine temperature sensors
Electrical thermostats

Question 20

What are sensing circuits

Answer 20

Turn on or increase the power to components depending on the conditions that they are in