Electrical Circuits

Question 1

What is constant in a series circuit

Answer 1

Current at every point in a series circuit is the same

Question 2

What happens to current at a junction in a parallel circuit?

Answer 2

The sum of the currents entering the junction equals the sum of the currents leaving the junction

Question 3

Series circuit calculations (3)

Answer 3

Current is constant
Voltage = v1 + v2
Resistance = r1 + r2

Question 4

How does total p.d. behave in a series circuit?

Answer 4

The total p.d. across the components is equal to the sum of the individual p.d.s across each component

Question 5

What is the p.d. across each branch of a parallel circuit

Answer 5

The p.d. across any branch in a parallel arrangement is the same as the p.d. across the whole parallel combination

Question 6

Parallel circuit calculations

Answer 6

Voltage is constant
current = I1 + I2
Resistance = 1/r1 + 1/r2 —> answer is the reciprocal

Question 7

Unit of power

Answer 7

Watts

Question 8

How do you find total emf of several sources in series

Answer 8

Add the individual emf values together

Question 9

What is the current like in the source in a parallel circuit compared to each branch

Answer 9

The current from the source is larger than the current in each branch

Question 10

How does the combined resistance of two resistors in parallel compare to each resistor alone

Answer 10

The combined resistance is less than the resistance of either resistor by itself

Question 11

Why are lamps in household lighting circuits connected in parallel (3)

Answer 11

• Each lamp receives the full pd
• each lamp can be controlled independently
• if one lamp fails the others continue to work

Question 12

What happens to current at a junction in a circuit

Answer 12

The sum of currents entering the junction equals the sum of the currents leaving the junction