The period of the musical node E0 is 4.85 * 10-2 seconds. What is the frequency of this note? Select one of the options below as your answer:. A. 10.8 hertz. B. 20.6 hertz. C. 40.8 hertz. D. 48.5 hertz. E. 80.9 hertz

Frequency, f = 1/T, Period T = 4.85 * 10 ⁻² s

f = 1 / (4.85 * 10 ⁻²)

f ≈ 20.619 ≈ 20.6

The frequency is B. 20.6 Hertz

Here's an interesting factoid to remember:

(Period of any wave) x (Frequency of the wave) = 1.

If you can memorize that, then you'll always remember that

Period = 1 / frequency

and

Frequency = 1 / period.

The second one is what you need for this problem.

Frequency = 1 / period

= 1 / (4.85 x 10⁻² second)

= 1 / (0.0485 second)

= 20.62 / second

= 20.62 Hz. (rounded)