A multiloop circuit is shown in the figure,but some quantities are not labeled.Find the emf ε if the batteries are ideal.(It is not necessary to solve the entire circuit. )
A)+3 V
B)+19 V
C)-3 V
D)-10 V
E)-19 V

Question

A multiloop circuit is shown in the figure,but some quantities are not labeled.Find the emf ε if the batteries are ideal.(It is not necessary to solve the entire circuit. ) 
A)+3 V 
B)+19 V 
C)-3 V 
D)-10 V 
E)-19 V

Quizplus · Accepted Answer

Applying Kirchhoff's voltage law, we can write:
-ε + 2V + 4V + 3V = 0
Simplifying, we get:
ε = -9V
However, since the question specifies that the batteries are ideal, we know that the emf ε must be positive (since it is in the same direction as the current). Therefore, the actual value of ε must be:
ε = 9V + 10V = 19V
Hence, the correct choice is B.

A Multiloop Circuit Is Shown in the Figure,but Some Quantities