A student wishes to make the magnetic force exerted by the electromagnet shown below greater. Which procedure step could the student follow to accomplish this goal?

*
1 point
Captionless Image
increase the length of wire at location 1
open the switch at location 2
add more batteries in series at location 3
reduce the number of wire turns at location 4

To make the magnetic force exerted by the electromagnet shown greater, the student could add more batteries in series at location 3.