$8$ Sam makes an electromagnet. He coils a wire around a big iron nail. He connects the ends of the wire to a battery. Sam uses his electromagnet to pick up paperclips.

Sam then changes the number of coils of wire around the nail.

He wants to answer the question:

How does the number of coils affect the strength of the electromagnet?

Each time he changes the number of coils, he counts the number of paperclips his electromagnet will lift.

$($a$)$ Which of these should Sam keep constant during his investigation. Tick $(\sqrt[\phantom{2}]{?})$ all that are correct.

size of the paperclips number of turns in the coil temperature of the paperclips

current in the coil material of the paperclips type of switch in the circuit

$($b$)$ The table shows Sam's results.

$\backslash$table$[[$Number of turns on the coil,Number of paperclips lifted$],[5,1],[10,2],[15,4],[20,5],[25,10],[30,12],[35,16]]$

$($i$)$ Complete this sentence about the results.

As the number of turns on the coil increase, the number of paperclips lifted incr.ease This means the electromagnet gets Stronger. as the number of turns on the coil increases.

$($ii$)$ Draw a circle around the anomalous result in the table.

$($iii$)$ How can Sam check his results to confirm$()$ this one was anomalous?

$($c$)$ Sam makes a conclusion from his results.

I can make my electromagnet stronger by adding more coils.

Write down one other way that he could make his electromagnet stronger.

U$.$se$...$

more

cells to

increase the

current

the

greater rcurrent,