Question

What is the frequency of a wave having a period equal to 18 seconds? a. 6.6 × 10-2 hertz b. 5.5 × 10-2 hertz c. 3.3 × 10-2 hertz d. 1.8 × 10-2 hertz e. 8.0 × 10-3 hertz

Answer 1

Frequency = 1/period. ... 1 / 18 sec = (1/18) per sec. That's 0.056 per sec or 0.056 Hz. (rounded) (5.6 x 10^-2 Hz)

Answer 2

Answer: Option (b) is the correct answer.

Explanation:

The time taken by a wave crest to travel a distance equal to the length of wave is known as wave period.

The relation between wave period and frequency is as follows.

                    $T = \frac{1}{f}$

where,        T = time period

                   f = frequency

It is given that wave period is 18 seconds. Therefore, calculate the wave period as follows.

                           $T = \frac{1}{f}$

 or,                      $f = \frac{1}{T}$

                                     = $\frac{1}{18 sec}$

                                     = 0.055 per second          (1 cycle per second = 1 Hertz)

or,                           f = $5.5 \times 10^{-2} hertz$

Thus, we can conclude that the frequency of the wave is $5.5 \times 10^{-2} hertz$.