AQA AS Electricity & Circuits

Question 1

Electric current

Answer 1

The net flow of charged particles per unit time through a point. Unit; amp. Conventional current flows positive to negative.

Question 2

Potential Difference

Answer 2

Energy transferred per unit charge when electrical energy is converted into another form of energy. 1 volt is 1 Joule per amp.

Question 3

Resistance

Answer 3

A materials opposition to the flow of electric current, measured in Ohms.

Question 4

Ohm’s Law

Answer 4

For a given material the voltage is directly proportional to current at a constant temperature.

Question 5

Kirchoff 1

Answer 5

The sum of the currents entering any point in a circuit is equal to the sum of the currents leaving that same point. Charge is conserved.

Question 6

Kirchoff 2

Answer 6

Sum of EMFs around a circuit loop = sum of PDs around that loop. Energy is conserved.

Question 7

Drift velocity

Answer 7

Average distance travelled by electrons in the wire per second. When a potential difference is applied, the electrons move slowly through the metal and collide constantly

Question 8

LDR

Answer 8

Light-dependent resistors. In bright light the resistance falls

Question 9

Thermistor

Answer 9

Hot-resistance drops.