Wave Basics

Question 1

What is meant by the frequency of a wave? What are the units of frequency?

Answer 1

Frequency is the number of complete cycles of a wave passing a certain point per second. The unit of frequency is hertz (Hz)

Question 2

Do waves transfer energy, matter or both? Give evidence of this with a real-life example.

Answer 2

Waves transfer energy but not matter. E.g. if you drop a twig into calm water, ripples form and move across the surface, without carrying the water or the twig away with them.

Question 3

How do vibrations of a longitudinal differ from the vibrations of a transverse wave? Give an example of a longitudinal wave and a transverse wave.

Answer 3

The vibrations of a longitudinal wave are parallel to the wave’s direction of travel, whereas the vibrations of a transverse wave are at 90° to the wave’s direction of travel.
Longitudinal waves: sound waves, P-waves.
Transverse waves: EM waves, S-waves, water waves

Question 4

Abhik uses a signal generator to create 20 Hz waves in a string. Abhik has calculated that the waves should travel with a speed of 4m/s. If Abhik’s calculations are correct, what will the wavelength of the waves on the string be?

Answer 4

0.2m
Use the equation v = f x λ
Substitute in the values for v and f: 4 = 20 x λ
Rearrange to make λ the subject: λ = 4 / 20 = 0.2m