17. elaine connects an ammeter to a lamp, which is connected to a battery. she records the current. she connects another battery in series to the circuit and records the ammeter reading again. she repeats this step two more times.

a) which variable is elaine not changing?
b) which variable is elaine changing?
c) which variable is elaine studying?
d) what do you expect elaine's readings to show?

18. mary measures the current in a long, thin extension cord. she unplugs the cord and switches it for a shorter, thicker one. what will mary observe if she measures the current through the new extension cord?