Every card in Electricity and magnetism, Year 8: more practice
The whole deck, in order — so you can read it through before your child ever sees it.
- A meter reads a current of 0.25 A. How many milliamps (mA) is that? (number only)
250
Hint1 A is 1000 mA.
WhyMultiply amps by 1000 to get milliamps: 0.25 × 1000 = 250 mA.
- Why does an electromagnet stop attracting paper clips when the circuit is switched off?
The current stops, so the magnetic field stops
HintWhat flows through the coil to make it act as a magnet?
WhyA coil's magnetic field exists only while current flows. An iron core stays magnetised only weakly and briefly, so the clips drop.
- The coil of an electromagnet is wound the opposite way round, so the current flows the other way. What changes about the magnet?
Its north and south poles swap
HintReverse the current and the ends reverse too.
WhyThe direction of the magnetic field depends on the direction of the current. Reversing the current reverses the poles.
- The meter drawn as a circle with the letter V inside it
A voltmeter
HintThe letter is the first of the quantity it measures.
WhyA voltmeter measures potential difference. It is drawn as a circle containing V.
- The component drawn as a plain rectangle on a circuit diagram
A resistor
HintIt resists the flow of current.
WhyA resistor is a rectangle on the wire. A variable resistor is the same rectangle with an arrow through it.
- Why do circuit diagrams use straight lines and standard symbols?
So anyone can read and build the same circuit
HintThe aim is agreement between different people.
WhySymbols are international, so a diagram can be understood without words and without being redrawn to look like real parts.
- A bulb transfers energy to its surroundings as light and heat. Is the current used up in the bulb?
No: the current is the same after the bulb as before
HintCompare ammeter readings either side of it.
WhyThe charge flows round the whole loop and is not used up. It is the energy it carries that is transferred in the bulb.
- What is the unit of potential difference?
The volt (V)
HintIt is named after a scientist.
WhyPotential difference is measured in volts, with a voltmeter connected across the component.
- Two 1.5 V cells are joined end to end in series. What is the total potential difference in volts? (number only)
3
HintSeries cells add together.
WhyThe voltages of cells in series add up: 1.5 V + 1.5 V = 3 V.
- Two identical bulbs are each connected in parallel to the same battery. How does the brightness of each compare with a single bulb on that battery?
The same
HintEach branch gets the full push of the battery.
WhyIn a parallel circuit each branch gets the full potential difference of the battery, so each identical bulb is as bright as one on its own.
1★ KS3-PHYS-ELE-0051
2★ KS3-PHYS-ELE-0052
3★ KS3-PHYS-ELE-0053
4★ KS3-PHYS-ELE-0054
5★ KS3-PHYS-ELE-0055
6★ KS3-PHYS-ELE-0056
7★ KS3-PHYS-ELE-0057
8★ KS3-PHYS-ELE-0058
9★ KS3-PHYS-ELE-0059
10★ KS3-PHYS-ELE-0060
Keep what you learn
Here, nothing is saved. In your child’s own sky every card is scheduled — it comes back just before they’d forget it — and the professor who wrote it is one tap away.