Question

A young child is playing with a very flexible hose. She is moving her hand back and forth making transverse type waves. She moves her hand back and forth faster (meaning that she makes more back and forth motions every second), but nothing else about the way she moves her arm or the hose changes. Which the following is true about the waves that she will see

O The waves will increase in frequency
O The waves will increase in wavelength
O The wave speed will increase pe waves.

Answer 1

The waves will increase in frequency

Step-by-step explanation:

As the young girl moves her hand back and forth faster, it will be observed that number of back and forth motions increase every second. Also the distance between crest and trough of the wave (wavelength) will be reduced as she moves her hand back and forth faster.

Frequency = number of turns (moves) per second

The waves will increase in frequency since there will be more number of back and forth motions in every second.

Also,

The distance between crest and trough will be reduced, which implies that there will be decrease in waves wavelength.

This can also be verified using wave equation;

V = Fλ

At constant velocity,

F ∝ ¹/λ

Thus, decrease in wavelength will cause increase in frequency of the waves.

The right answer is : The waves will increase in frequency