WAEC 2016 Physics · Question 15

The distance between two successive trough of a wave is 0.4m. If the frequency of the source is 825Hz, Calculate the speed of the wave

Options

A.165.0 $ms^{-1}$
B.330.0 $ms^{-1}$
C.41.5 $ms^{-1}$
D.85.0 $ms^{-1}$

Answer: B. 330.0 $ms^{-1}$

Explanation written with AI and checked against the answer key

Analyze the question: The distance between two successive troughs is one full wavelength, so λ = 0.4 m. The frequency is f = 825 Hz, and we want the wave speed. Concept: The wave equation links speed, frequency and wavelength: v = fλ Solution: v = 825 × 0.4 v = 330 m/s Checking the options: The result is 330.0 m/s, which matches option B. This is also close to the speed of sound in air, so it is a sensible value. Answer: B. 330.0 m s⁻¹ Tip: "Distance between two successive crests or troughs" always means one wavelength (λ). Don't halve it or double it. Then just use v = fλ. Be careful with the arithmetic: 825 × 0.4 = 330, not 165 (that would come from using 0.2 m).

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The distance between two successive trough of a wave is 0.4m. If the frequency of the source is 825Hz, Calculate the speed of the wave

Options

Answer: B. 330.0ms−1ms^{-1}ms−1

Answer: B. 330.0 $ms^{-1}$