Sixty complete waves pass a particular point in 4s. If the distance between three successive troughs of the waves is 15 m, calculate the speed of the waves.
A
75.0 ms\(^{-1}\)
B
225.0 ms\(^{-1}\)
C
300.0 ms\(^{-1}\)
D
112.5 ms\(^{-1}\)
Verified Correct Answer: D.
Step-by-Step Mathematical Solution
f = \(\frac{\text{no of oscillation made}}{t(s)}\) = \(\frac{60}{4}\) = 15 Hz
This distance equals 2 wavelengths (because there are 3 troughs, each with 2 intervals between them).
2\(\lambda\) = 15
\(\lambda\) = \(\frac{15}{2}\) = 7.5m
V = f\(\lambda\)
v = 15 × 7.5 = 112.5 ms\(^{-1}\)
Source: WAEC / JAMB / NECO Classroom Archive (Record #76374)