Passage 12472

Question

Directions: Read the passage about the factors that affect the magnetism of electromagnets.

An electromagnet consists of an insulated copper wire wound around an iron core and connected to a source of electricity. The magnetism of electromagnets disappears when the electricity is turned off. A student performs two experiments to study the factors that affect the magnetism produced by an electromagnet.

Experiment 1

He prepares an electromagnet by wrapping ten coils of a wire around an iron nail. The wire is then connected to a 4.5-volt battery. Next, the electromagnet is placed close to evenly spread iron paper clip

He records the number of paper clips that are attracted to the magnet in a table, repeating the activity with different numbers of coils around the nail.

Number of coils Number of paper clips attracted to the magnet
10 6
15 11
20 17
25 23
Experiment 2

In his second experiment, he repeats the same procedure he used in Experiment 1, except that this time he keeps the number of coils the same but changes the battery voltage. He records the number of paper clips attracted each time in a second table.

Battery Voltage (V) Number of paper clips attracted to the magnet
3.0 3
4.5 6
6.0 9
7.5 13

Answer 1

The passage outlines two experiments conducted by a student to investigate the factors influencing the magnetism of electromagnets.

In Experiment 1, the student examines how the number of coils of insulated copper wire wrapped around an iron nail affects the strength of the electromagnet. The experiments reveal that as the number of coils increases, the number of paper clips attracted to the magnet also rises. Specifically:

• With 10 coils, 6 paper clips are attracted.
• With 15 coils, 11 paper clips are attracted.
• With 20 coils, 17 paper clips are attracted.
• With 25 coils, 23 paper clips are attracted.

This shows a clear correlation between the number of wire coils and the strength of the electromagnet.

In Experiment 2, the student keeps the number of coils constant but varies the voltage of the battery powering the electromagnet. The findings indicate that increasing the voltage also increases the number of paper clips attracted:

• At 3.0 volts, 3 paper clips are attracted.
• At 4.5 volts, 6 paper clips are attracted.
• At 6.0 volts, 9 paper clips are attracted.
• At 7.5 volts, 13 paper clips are attracted.

Both experiments suggest that both the number of coils of wire and the voltage of the battery are significant factors that affect the magnetism produced by an electromagnet.