The figure shows variation of the current through the heating element with time in an iron when it is plugged into a standard 120 V,60 Hz outlet.

-What is the resistance of the iron?
A)24
B)7.1
C)17
D)12
E)1.8

Question

The figure shows variation of the current through the heating element with time in an iron when it is plugged into a standard 120 V,60 Hz outlet.
 
-What is the resistance of the iron?
A)24 
B)7.1 
C)17 
D)12 
E)1.8

Quizplus · Accepted Answer

The resistance of the iron can be found using Ohm's Law, which states that V=IR where V is the voltage, I is the current, and R is the resistance. 
From the graph, we can see that the maximum current is around 7.1 amps. Using Ohm's Law, we can calculate the resistance as R=V/I, where V is 120 volts and I is 7.1 amps. 
R = 120/7.1 = 16.9 ohms 
Therefore, the best choice is C, which is the closest value to 16.9 ohms.

The Figure Shows Variation of the Current Through the Heating