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 rms value of the current in this circuit?
A)1.4 A
B)7.1 A
C)11 A
D)14 A
E)18 A

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 rms value of the current in this circuit?
A)1.4 A 
B)7.1 A 
C)11 A 
D)14 A 
E)18 A

Quizplus · Accepted Answer

To find the rms (root mean square) value of the current, we need to use the formula:

Irms = Ipeak / √2

where Ipeak is the maximum current. From the graph, we can see that the maximum current is around 10 A. 
So, 
Irms = 10 A / √2 ≈ 7.1 A

Therefore, the best choice is B.

The Figure Shows Variation of the Current Through the Heating