# Electricity - Structured questions

Simple recall questions are usually worth one mark. They are often have command words like 'give', 'state', 'name' or 'identify'. Some questions may ask you to state two things, rather than just one, and will be worth two marks.

Structured questions, with command words such as 'describe' or 'explain', will be worth two or more marks:

• if you are asked to describe something, you need to give an account but no reason
• if you are asked to explain something, you must give reasons or explanations

More complex structured questions will be worth three to five marks. They include questions with complex descriptions and explanations, questions in which you need to compare and contrast two different things, or calculations with several stages.

The mark schemes given here may show answers as bullet points. This is to show clearly how a mark can be obtained. However, it is important that your answer is written in a logical, linked way.

Questions courtesy of Eduqas.

## Sample question 1 - Foundation

Question

a) Two identical lamps, each of resistance 8 Ω, are connected in parallel. They are connected to a 12 V battery and switched on.

i) Recall the equation and use it to calculate the current through one lamp. [2 marks]

ii) What is the reading on the ammeter? [1 mark]

iii) Recall an equation to calculate the power of one lamp. [2 marks]

The same two lamps are now connected in series with the same battery. The resistance of the circuit has now increased so it is four times bigger than when the lamps were in parallel.

b) Describe fully the effect this has on the current through the battery. [2 marks]

a) i) [1]

[1]

ii) [1]

iii) [1]

[1]

b) Current reduces by a factor of 4 [1] to 0.75 A [1].

## Sample question 2 - Higher

Question

a) Give a reason why lamps are connected in parallel in household lighting circuits. [1 mark]

The following circuit is set up to investigate the power of different lamps when they are connected in parallel:

b) Describe how the power of lamp X can be determined, naming any components required. [3 marks]

c) You will need to recall equations to answer the following questions:

i) The power of lamp X is 2.5 W and its resistance is 10 Ω. Calculate the current through it. [3 marks]

ii) The ammeter reading is 0.75 A. Use this information to calculate the resistance of lamp Y. [3 marks]

iii) Calculate the ratio of the power of lamp X to the power of lamp Y. Show your working. [2 marks]

a) Can be switched independently/if one bulb fails others continue to work/have the same (mains) voltage across them/maintain their brightness when other lamps are switched on. [1]

b) Connect an ammeter in series with the lamp X [1]. Connect a voltmeter in parallel with/across lamp X [1]. Then multiply the two readings as: [1].

c)i) [1]

[1]

the current through lamp X [1]

ii) Current through lamp Y = 0.75 - 0.5 = 0.25 A

V across X = V across Y = IR = 0.5 × 10 = 5 V [1]

[1]

[1]

iii) Power of X = IV = 0.5 × 5 = 2.5 W

Power of Y = IV = 0.25 × 5 = 1.25 W

[1]

Ratio of Power = 2:1 [1]