A current, having a root-mean-square of 13 A will do the same amount of work as a d.c. current of
A) 9.2 A
B) 13 A
C) 18.4 A

Question

Quizplus · Accepted Answer

Root-mean-square (RMS) current is used to represent the effective current, which is equivalent to the DC current that delivers the same amount of energy in a given time period. Therefore, a current having an RMS value of 13A (Irms) would do the same amount of work as a DC current (Idc) that delivers the same power over time. The relationship between RMS and DC current is as follows:

Irms = Idc / sqrt(2)

Rearranging the formula, we get:

Idc = Irms * sqrt(2)

Substituting the values, we get:

Idc = 13A * sqrt(2) ≈ 18.4A

Therefore, the current having an RMS value of 13A is equivalent to a DC current of approximately 18.4A. However, since none of the choices match exactly, the best answer is B) 13A, as it is the only choice that is closest to the calculated value.

A Current, Having a Root-Mean-Square of 13 a Will Do