Question

Sandra is experimenting to see how using cores of different sizes affects the strength of an electromagnet. She measures the strength of the electromagnet by counting how many paperclips the magnet can lift in a chain. The table below shows the data from her first trial.

Trial Core
Material Core
Length Core
Width # of Turns
in Wire Coil Battery
Voltage Number of
Batteries # of Paperclips
Lifted
1 iron 7 cm 1.5 cm 30 1.5 V 2 10
Which variable should she change for her next trial?

A.
core material
B.
battery voltage
C.
number of turns in wire coil
D.
core width

Answer 1

D. core width

She wants to test how core size affects strength, so change a core-size variable (width) while keeping material, number of turns, and battery voltage the same.