WAEC Physics 2020 Objective — Question 39
Question 39 of 50 from the West African Examinations Council (WAEC) Physics 2020 Objective paper, with the correct answer and a full explanation.
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Water waves have a wavelength of 3.6 cm and speed of 18 cm/s in deep water. If the waves enter a shallow water with wavelength of 2.0 cm, calculate the speed of the waves in the shallow water.
- A. 0.4 cm/s
- B. 2.5 cm/s
- C. 10.0 cm/sCorrect
- D. 10.8 cm/s
Explanation
Given v1=18cm/s, lambda1=3.6cm, lambda2=2.0cm, v2=? Using n=v1/lambda1=v2/lambda2, v2=v1x(lambda2/lambda1)=18x(2.0/3.6)=10 cm/s.
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