An electromagnet constructed by a student lifts $15$ paper clips when connected to a $2\text{ A}$ current…
An electromagnet constructed by a student lifts $15$ paper clips when connected to a $2\text{ A}$ current source. Assuming the magnetic strength increases proportionally with current, how many paper clips will it lift if the current is increased to $4\text{ A}$?
$15$ clips
$20$ clips
$30$ clips
$60$ clips
Solution
Doubling the electric current from $2\text{ A}$ to $4\text{ A}$ doubles the electromagnet's magnetic strength, so it will lift $15 \times 2 = 30$ paper clips.