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

which variable should she change for her next trial?
a. number of batteries
b. number of turns in wire coil
c. core material
d. core width

Explanation:

Sandra is testing the effect of core size on electromagnet strength. Core size includes length and width. Since length is already tested, width is the logical core - size variable to change next.

Answer:

D. core width