Question

Suppose we measure the energy stored in some inductor to be E when there is a current I running through it. If I double the current in the inductor, the new total energy will become _____.

a. 8E
b. 2E
c. E
d. E/4
e. E/2
f. 4E

Answer 1

If I double the current in the inductor, the new total energy will become 4E (option f).

Step-by-step explanation:

The coil or inductor is a passive component made of an insulated wire that stores energy in the form of a magnetic field due to its form of coiled turns of wire, through a phenomenon called self-induction. In other words, inductors store energy in the form of a magnetic field. The energy stored in the space where there is a magnetic field in the inductor is:

`E=(1)/(2) *L*I^(2)`

where E is Energy [J], L is Inductance [H] and I is Current [A].

If you double the current in the inductor, then the new value of the current is I'= 2*I. So replacing the new total energy is:

`E'=(1)/(2) *L*I'^(2)=(1)/(2) *L*(2*I)^(2)=(1)/(2) *L*4*I^(2)=4*(1)/(2) *L*I^(2)`

Then:

`E'=4*E`

If I double the current in the inductor, the new total energy will become 4E (option f).