Read the passage and answer the following question(s).

Question

Passage 12472

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

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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
Another student made an electromagnet with an iron nail with eight coils of wire wound around it connected to a 2-V battery. She wants to increase the strength of the electromagnet.

What changes can she make to her design to increase its strength? Select all that apply.
A.
use a shorter wire

B.
use a 4-V battery

C.
wrap more coils of wire around the nail

D.
reduce the coils of wire from eight to six

E.
use two 1-V batteries instead of a 2-V battery

Answer 1

To increase the strength of the electromagnet, the student can make the following changes:

B. use a 4-V battery
Increasing the voltage would increase the strength of the electromagnet.

C. wrap more coils of wire around the nail
Adding more coils increases the strength of the magnetic field produced by the electromagnet.

E. use two 1-V batteries instead of a 2-V battery
Using two 1-V batteries in series would provide a total of 2 volts, which does not increase the voltage beyond what is already being used. However, since this option doesn't decrease voltage or increase it beyond 2-V, it is not an effective way to strengthen the magnet. Hence, this option is irrelevant.

In summary, the correct answers to increase the electromagnet's strength are B and C.