Measuring Waves

Waves Review

By Israel Hinojosa

​There are 2 categories of waves

​Mechanical Waves

• Require a medium

• cannot travel through space

• ex: sound, ocean waves

​Electromagnetic Waves

• Don't require medium

• can travel through space

• ex: light, uv rays, radio waves​

​There are 2 types of waves

​Transverse Waves

• travel up and down

• perpendicular to flow of energy​

​Longitudinal Waves

• Travel side to side

• parallel to flow of energy

​Transverse Waves

​Know the 4 parts of the transverse wave

​

Crests and Troughs are used for measuring wavelength

​

Amplitude is how high the wave goes​

Longitudinal Waves

​Know the 2 parts of the wave

​

Compressions and Rarefactions are used for measuring wavelength

​​

Multiple Choice

What is number 2 called?

• crest

• trough

• wavelength

• amplitude

Multiple Choice

What is number 3 called?

• crest

• trough

• wavelength

• amplitude

Measuring Wavelength

Make sure you can measure the wavelength when given a picture of a wave​

​

Always remember you are measuring from one point to that same point later in the wave

​​

Fill in the Blank

What is the wavelength of the wave shown in the picture?

Multiple Choice

If this wave was traveling at a speed of 3m/s what would be the frequency of the wave?

• 3 Hz

• 1.5 Hz

• 1.33 Hz

• 0.75Hz

Multiple Choice

What type of wave requires a medium?

• Electromagnetic

• Gamma

• Mechanical

• Radio

Calculating velocity of waves

Velocity (m/s)

Frequency (Hz)

wavelength (m)​

​​

Ex:​

​A tuning fork has a frequency of 120 Hz, and the wavelength of the sound produced is 4 meters. What is the velocity of the wave rounded to the nearest whole number? 

Calculating frequency

f = Frequency (Hz)

T = Period (s)​

​​

This equation is used when you need to find frequency and all you have is time. Also can be rearranged to find period if you have the frequency by switching the f and the T in the equation

Fill in the Blank

A wave with a frequency of 800 Hz is traveling at a speed of 900 m/s. What is the wavelength rounded to the nearest tenth?

$$v=\lambda\times f$$

Fill in the Blank

A wave has a frequency of 12.56 Hz. What is the period of the wave?

(round to the nearest hundredths)

$$f=\frac{1}{T}$$

Fill in the Blank

A wave has a wavelength of 155 meters and is moving at a speed of 230 m/s. What is its frequency? (round to the nearest hundredths place)

$$v=\lambda\times f$$

Fill in the Blank

What is the velocity of a wave if it has a period of 3.4 s and a wavelength of 2 m?

(round to the nearest hundredths place)

$$f=\ \frac{1}{T}$$ $$v=\lambda\times f$$

Electromagnetic spectrum

Multiple Choice

Based on the electromagnetic spectrum who's lightsaber has more energy? (think about the color of the lightsaber)

• Luke Skywalker

• Darth Vader

Multiple Choice

Which wave would have the highest frequency

• microwaves

• x-rays

• blue light

• Infra red

Wave interactions: Reflection

​Reflection happens when a wave hits a surface and bounces off.

​

If the wave comes in at an angle, it will bounce away at that same angle​

Wave interactions: Diffraction

​Diffraction happens when a wave hits an opening or a corner and bends around the corners causing it to spread in all directions on the other side.

Wave interactions: Refraction

​Refraction happens when a wave changes mediums causing it to change in speed and bend as a result.