What is the second harmonic of a frequency at 380 kHz?

To determine the second harmonic of a given frequency, you multiply the fundamental frequency by two. In this case, the fundamental frequency is 380 kHz.

So, calculating the second harmonic involves the following:

Second harmonic = 2 × Fundamental frequency

Second harmonic = 2 × 380 kHz

Second harmonic = 760 kHz

This calculation shows that the second harmonic of 380 kHz is indeed 760 kHz. The other choices either represent frequencies that are not the result of the appropriate multiplication needed to find the second harmonic or are simply the original frequency or half of it, which do not represent harmonic frequencies in this context.