Chapter 5 Practice Paper: Electrical Systems — mark scheme (print)

Back to Chapter 5

Question paper PDF

QuizQuipPractice Series

QQ/S2SCI/CH5

Secondary 2 · Lower Secondary Science (G2 / G3)

Mark scheme

Electrical Systems

Chapter 5 Practice Paper · Maximum mark: 30

Notes for markers

Award one mark for each point marked [1], up to the marks shown for the part.
Accept answers worded differently that show the same understanding.
Units are required where the answer line shows one. ecf: allow an error carried forward.

Section A: Multiple-choice questions[10 marks]

Question	Answer
1	AAn ammeter is connected in the circuit so the current passes through it. A voltmeter is connected across a component.	1
2	CThe voltmeter measures potential difference across a component. It is not placed in the single path the way an ammeter is.	1
3	BResistance is the quantity, in ohms. A resistor is the component. Current is in amperes and potential difference is in volts.	1
4	DThe thin fuse wire melts before the cable overheats.	1
5	AThey share one path. The gap stops the current, so the porch lamp goes out as well.	1
6	CEach bulb has its own path. Removing one bulb does not break the path of the others.	1
7	DDamaged insulation lets the current leave the intended path.	1
8	BThe watt is the unit of power. A higher power transfers energy faster.	1
9	AThe heating effect is used in kettles and filament lamps.	1
10	CA fixed resistor is a rectangle. The arrow shows that the resistance can be changed.	1

Section B: Structured questions[20 marks]

Question	Answer and marking points	Marks
1(a)	Current, in amperes. Current [1] Ampere / A [1]	2
1(b)	Potential difference, in volts. Potential difference / voltage [1]	1
1(c)	A resistor. It provides resistance, measured in ohms. Resistor [1] Resistance, in ohms [1]	2
	Total for Question 1	5
2(a)	The rear lamp goes out. There is only one path, so the gap stops the current. The rear lamp goes out [1] The series circuit has only one path [1]	2
2(b)	The rear lamp stays on. It still has its own complete path back to the cell. The rear lamp stays on [1] It has its own complete path [1]	2
2(c)	One lamp can be off, or can fail, while the others stay on. One lamp can be off while the others stay on [1]	1
	Total for Question 2	5
3(a)	The thick wire will not melt when the current is too large. The cable can then overheat. The wire will not melt at the safe current [1] The cable can overheat [1]	2
3(b)	Water can conduct, so a shock is more likely. Water can conduct / a shock is more likely [1]	1
3(c)	The current is larger than the lead is meant to carry. The lead heats up and may start a fire. The current is too large for the lead [1] The lead overheats / may cause a fire [1]	2
	Total for Question 3	5
4(a)	The watt (W). Watt / W [1]	1
4(b)	The toaster. It has the higher power, so it transfers energy faster in the same time. The toaster / 800 W appliance [1] Higher power means energy is transferred faster [1]	2
4(c)	Any one: switch off unused lights; do not leave a heater on in an empty room. A valid way of using less energy [1]	1
4(d)	Any one: charging a rechargeable battery; plating a metal. Charging a battery or plating a metal [1]	1
	Total for Question 4	5

— End of mark scheme —