Series And Parralel Circuits

Question 1

What do components in a series circuit have?

Answer 1

• same current through each component
• the total p.d of the power supply is shared between components
• the total resistance of 2 components is the sum of the resistance of each component.

Question 2

What do Components connected in parallel have?

Answer 2

• the p.d across each component is the same
• the total current through the whole circuit is the sum of the currents through the separate components. - split across branches
• the total resistance of two resistors is less then the resistance of the smallest individual resistor.

Question 3

Why is the totals resistance smaller in a parallel circuit?

Answer 3

Because each resistor added creates an extra path which current can flow. This means that there is a larger total current that is flowing through the circuit. Lower resistance.

Question 4

Why does the resistance increase in series

Answer 4

Because the current has more resistors to pass through therefore more collisions. Lower current = increase resistance

Question 5

What is mains electricity and what is it in the UK?

Answer 5

Mains electricity is an ac supply. In UK the domestic electricity supply has a frequency of 50Hz and is 230v

Question 6

Direct current

Answer 6

DC is electrical current flowing in one direction. Usually found in battery powered devices.

Straight line on graph

Question 7

Alternating current

Answer 7

Current that changes direction from positive to negative periodically. Eg UK mains supply. Current from sockets in home

Wave on a graph

Question 8

What happens to resistance of circuit series but the resistors are in parallel?

Answer 8

The total resistance of the circuit would be less then 20 as the resistance of the lamp would be added to the total resistance of the resistors in parallel. The resistance in parallel have a total resistance of less then 10. Lamp = 10 originally

Question 9

How will potential difference across the lamp and resistor will change when switch is closed? Circuit is series with parallel resistor.

Answer 9

The resistor - p.d across resistor will be 0v because there’s no current in the resistor
The lamp - p.d would increase as more current is flowing through the lamp