Question

The distance between four consecutive crests of wave is 120 cm. If the waves are produced at the rate of 240 per minute, calculate (i) wavelength (ii) time period (iii) wave velocity. *​

Answer 1

★ Solution:-

Distance between four consecutive crests = 3 λ

As per the given data ,

• Distance between four consecutive crests = 120 cm

Hence we can conclude that ,

➽ 3 λ = 120

➽ λ  = 120 /3

➽ λ  = 40 cm

Wavelength = 40 cm

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Now in order to find time period first we need to find the frequency of the wave

As per the question ,

• n = 240 / min

We need to convert this into Hertz in order to do that first let us convert the min into sec in order to do that simply divide by 60

• n = 240 / 60 = 4 s-¹ = 4 Hz

we know that ,

➽ T = 1 / n

➽ T = 1 / 4

➽ T = 0.25 s

Time period = 0.25 s

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As per the formula ,

➽ v = n λ

➽ v = 4 x 40

➽ v = 80 cm /s

Wave velocity = 80 cm/s