Direct current circuits

Question 1

Circuit rules for current (Kirchhoff’s 1st law)

Answer 1

1. The current passing through two or more components in series is the same through each component
2. At a junction, the total current in = the total current out

Question 2

Circuit rules for pd (Kirchhoff’s 2nd law)

Answer 2

1. For two or more components in series, the total pd across all the components is equal to the sum of the pds across each component
2. The sum of the emfs round a complete loop in a circuit = the sum of the pds round the loop

Question 3

Internal resistance

Answer 3

Resistance inside a source of electrical energy; the loss of pd per unit current in the source when current passes through it

Question 4

Electromotive force (emf)

Answer 4

The amount of electrical energy per unit charge produced inside a source of electrical energy

Question 5

Light-dependent resistor

Answer 5

Resistor designed to have a resistance that changes with light intensity

Question 6

Thermistor

Answer 6

Resistor designed to have a resistance that changes with temperature