Wave Properties — Drills · Grade 8 Science

Chapter: Waves, Sound & Light

What these drills covers

By the end of Wave Properties you should be able to:

8 questions, multiple choice, numeric and written answer, each with a worked explanation.

Vocabulary used: wave, amplitude, wavelength (λ), frequency (f), period (T), model, evidence, system boundary, assumption.

Problem 1

The distance from one wave crest to the next is the
  1. amplitude
  2. wavelength
  3. frequency
  4. period
Answer and explanation

wavelength

Wavelength is the distance over which the wave pattern repeats.

Problem 2

Frequency is measured in
  1. metres
  2. hertz
  3. newtons
  4. joules
Answer and explanation

hertz

One hertz is one complete wave per second.

Problem 3

A wave has frequency 5 Hz and wavelength 4 m. What is its speed in m/s?
Answer and explanation

20 m/s

speed = frequency × wavelength = 5 × 4 = 20 m/s.

Problem 4

A wave travels at 30 m/s with a wavelength of 6 m. What is its frequency in hertz?
Answer and explanation

5 Hz

frequency = speed / wavelength = 30/6 = 5 Hz.

Problem 5

A wave of speed 12 m/s has a frequency of 3 Hz. What is its wavelength in metres?
Answer and explanation

4 m

wavelength = speed / frequency = 12/3 = 4 m.

Problem 6

In a transverse wave the particles move
  1. along the direction of travel
  2. at right angles to the direction of travel
  3. in circles only
  4. not at all
Answer and explanation

at right angles to the direction of travel

Transverse motion is perpendicular to the wave's direction; longitudinal motion is along it.

Problem 7

Explain what a wave transfers and what it does not.
Answer and explanation

A wave transfers energy from one place to another. It does not transfer matter: the particles of the medium oscillate about their own positions and return there, as a floating object bobs up and down while a water wave passes beneath it rather than being carried along with it.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the data, mechanism, or calculation that supports it.
  • Include units, conditions, or limits where relevant.

Problem 8

Two waves have the same frequency but different amplitudes. Describe how they differ and what stays the same.
Answer and explanation

Amplitude is the size of the oscillation, so the larger-amplitude wave carries more energy — a louder sound or a brighter light. Frequency, and therefore wavelength at the same speed, is unchanged, so the pitch of a sound or the colour of a light stays the same. Amplitude and frequency are independent properties.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the data, mechanism, or calculation that supports it.
  • Include units, conditions, or limits where relevant.

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