At what rate is power supplied by the 10-V emf shown below?
A)-10 W
B)+10 W
C)zero
D)+20 W
E)-20 W

Question

At what rate is power supplied by the 10-V emf shown below? 
A)-10 W 
B)+10 W 
C)zero 
D)+20 W 
E)-20 W

Quizplus · Accepted Answer

The power supplied by the emf can be found using P = IV, where I is the current flowing through the circuit. Since the emf is connected to a short circuit, the current is given by I = V/R = 10/0 = infinity. However, infinite current is not physically possible, and in reality, the wires and components in the circuit would limit the current. Therefore, the actual current will be limited by the resistance of the circuit, which is not given in the question. Since we cannot calculate the actual current, we cannot calculate the power supplied by the emf accurately. However, we can say that the emf is capable of supplying a maximum power of 10 x infinity = infinity watts, which is represented by choice B. Therefore, choice B is the best answer.

At What Rate Is Power Supplied by the 10-V Emf