Refer to the following illustration to answer this question.

waves

to measure one wavelength, you would measure the distance between

c and a

c and f

d and b

c and e

C and E      

Explanation:

Wavelength of a wave is said to complete one wavelength when it it covers one wave i.e from one trough to one crest. It is also defined as the distance between two consecutive crests or two consecutive troughs.

The wave having longest wavelength will have least frequency as these two terms are inversely proportional to each other.

In the attached figure, distance between A to B shows one wavelength. Also, the distance between A and E shows one wavelength. Hence, the correct option is (d) " C and E ".

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