Test Index

WAEC Physics 2019 Paper

Question : 19

Total: 49

Solution:

Concept:

The wavelength of a wave is calculated by dividing its speed by its frequency.

Explanation:

First, find the speed of the pulse using the distance and time given.

Speed,

v = \frac{\text{distance}}{\text{time}} = \frac{4.5\ \text{m}}{0.6\ \text{s}} = 7.5\ \text{m/s}

The wave equation is

v = f \lambda

So, wavelength,

\lambda = \frac{v}{f}

Substitute

v = 7.5\ \text{m/s}

and

f = 9\ \text{Hz}

\lambda = \frac{7.5}{9} = 0.8333\ldots\ \text{m}

Rounding to two decimal places gives

0.83\ \text{m}

Answer:

\lambda = 0.83\ \text{m}

(Option C).

Go to Question:

Prev Question

Next Question