P4.3- Electrical circuits

Question 1

What stays constant around a series circuit

Answer 1

Current

Question 2

Series circuit calculations (3)

Answer 2

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

Question 3

What happens to current at a junction in parallel circuit

Answer 3

The sum of current entering junction = The sum of current leaving junction

Question 4

How does p.d behave in a series circuit

Answer 4

Total p.d across components = sum of individual p.d’s in each component

Question 5

What is the p.d across each branch of parallel resistance

Answer 5

The p.d across any branch in a parallel arrangement= p.d across the whole parallel combination

Question 6

Parallel circuit calculations [3]

Answer 6

Voltage is constant
current (total) = I1 + I2
Resistance(total) = 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 (cells) in series

Answer 8

add individual emf values together

Question 9

Compare the current in source (cells) with the current in each branch (of parallel)

Answer 9

Current at source is bigger (total of all branches)

Question 10

Compare combined resistance in a parallel vs them alone

Answer 10

Combined resistance is less than resistor on it’s own

Question 11

Why are lamps in a household lighting circuit connected in parallel [3]

Answer 11

1. Each lamp receives full pd
2. Each lamp controlled independently
3. If one fails, the other continues to work