Waves can be broadly classified into two main types: mechanical waves and electromagnetic waves.

1. Mechanical Waves: These are waves that need a material or medium (like air, water, or a solid) to travel through. They can be further divided into:
   • Transverse Waves: In these waves, the movement of the particles in the medium is perpendicular to the direction of the wave. An example is a water wave, where the water moves up and down as the wave travels horizontally.
   • Longitudinal Waves: In these waves, the particles in the medium move parallel to the direction the wave is traveling. Sound waves are an example, where air molecules move back and forth in the same direction as the wave.
2. Electromagnetic Waves: These waves do not need a medium and can travel through a vacuum (like space). They include light, radio waves, X-rays, and microwaves. Electromagnetic waves are always transverse and can travel at the speed of light.

Summary:

• Mechanical Waves need a medium (e.g., sound, water waves).
  • Transverse (e.g., water waves)
  • Longitudinal (e.g., sound waves)
• Electromagnetic Waves don’t need a medium (e.g., light, radio waves) and can travel through space.

Each type of wave has different behaviours and applications in the world around us!

How do we measure waves

There are 3 main components to waves which we need to measure:

1. Wavelength (λ): This is the distance between two consecutive points on a wave that are in phase, like the distance between two peaks. You can measure it in meters using a ruler or other measuring tool if it’s a physical wave like a ripple on water.
   
2. Frequency (f): Frequency refers to the number of waves passing a point in one second. It’s measured in Hertz (Hz). If you’re counting how many waves go by in a certain time, you can divide the number of waves by the time to find the frequency.
   
   
3. Wave Speed (v): Wave speed is how fast the wave is moving. You can calculate it using the formula: v = f × λ Where v is the wave speed (in meters per second), f is the frequency (in Hertz), and λ is the wavelength (in meters).

Simple Example:

• If you measure a wavelength of 2 meters and a frequency of 5 Hz, the wave speed would be:
  v=5 Hz×2 m=10 m/s

Here are 10 practice questions using the wave speed equation v = f × λ

1. A wave has a frequency of 4 Hz and a wavelength of 3 meters. What is the speed of the wave?
   
2. The speed of a wave is 25 m/s, and its frequency is 5 Hz. What is the wavelength?
   
3. If a wave has a speed of 15 m/s and a wavelength of 2 meters, what is the frequency of the wave?
   
4. A sound wave travels at 340 m/s, and its frequency is 85 Hz. What is the wavelength?
   
5. A wave has a wavelength of 0.5 meters and travels at a speed of 2 m/s. What is the frequency of the wave?
   
6. A wave with a frequency of 10 Hz travels with a speed of 50 m/s. What is the wavelength?
   
7. A wave with a wavelength of 0.2 meters has a frequency of 20 Hz. What is its speed?
   
8. If the speed of a wave is 100 m/s and the wavelength is 5 meters, what is the frequency?
   
9. A wave has a frequency of 7 Hz and travels with a wavelength of 0.4 meters. What is its speed?
   
10. The speed of a wave is 72 m/s, and its wavelength is 8 meters. What is the frequency of the wave?
    

Answers

Here are the answers from earlier formatted with HTML so they can be copied directly into WordPress:

1. Wave speed:

v = f × λ = 4 Hz × 3 m = 12 m/s

2. Wavelength:

λ = v / f = 25 m/s / 5 Hz = 5 m

3. Frequency:

f = v / λ = 15 m/s / 2 m = 7.5 Hz

4. Wavelength:

λ = v / f = 340 m/s / 85 Hz = 4 m

5. Frequency:

f = v / λ = 2 m/s / 0.5 m = 4 Hz

6. Wavelength:

λ = v / f = 50 m/s / 10 Hz = 5 m

7. Wave speed:

v = f × λ = 20 Hz × 0.2 m = 4 m/s

8. Frequency:

f = v / λ = 100 m/s / 5 m = 20 Hz

9. Wave speed:

v = f × λ = 7 Hz × 0.4 m = 2.8 m/s

10. Frequency:

f = v / λ = 72 m/s / 8 m = 9 Hz

Challenge Questions

Question 1:

A wave travels through a medium with a speed of 450 m/s. The frequency of the wave is doubled, but the speed remains the same. If the original wavelength was 15 meters, what is the new wavelength after the frequency is doubled?

Question 2:

A wave with a frequency of 8 Hz travels at a speed of 24 m/s. The medium then changes, reducing the speed of the wave to 18 m/s while keeping the frequency constant. What is the ratio of the new wavelength to the original wavelength?

Question 3:

A light wave with a speed of 3.0 × 10⁸ m/s has a wavelength of 600 nm (nanometers). Convert the wavelength to meters, and then find the frequency of the wave. (1 nm = 1 × 10⁻⁹ meters)

Q 1 Answer:

Q 2 Answer:

Q 3 Answer: