3. 2 Categories of Waves
2. Electromagnetic Waves
- are waves that do not require a
medium.
1. Mechanical Waves
- are waves that require a medium.
4. Mechanical Waves
• Mechanical waves require a
medium to transport their
energy from one location to
another.
• Slinky waves, water waves,
stadium waves, and jump
rope waves are other
examples of mechanical
waves; each requires some
medium to exist.
A sound wave is an example of a mechanical
wave. Sound waves are incapable of traveling
through a vacuum.
5. Electromagnetic Waves
• Electromagnetic waves are
produced by the vibration of
charged particles.
• Electromagnetic waves that
are produced on the sun
subsequently travel to Earth
through the vacuum of outer
space.
• Were it not for the ability of
electromagnetic waves to
travel to through a vacuum,
there would undoubtedly be
no life on Earth.
All light waves are examples of electromagnetic waves.
6. Well, where does light come from?
If it can travel through
NOTHINGNESS, then it
doesn’t need a medium
8. Wavelength
It is important
property of a wave.
In visible light, the
wavelength
determines its color.
Distance between two
successive crest or
troughs of transverse
wave
The symbol is λ and is measured in meters.
9. Frequency
Number of complete cycles or
waves that occur in a given
amount of time, measured in
hertz (Hz).
Hz = s-1 (also written as Hz =
1/s).
High-frequency music
has lots of quick changes
in the sound waves, and
it feels fast and
energetic.
Low-frequency music has slower changes in the sound waves, and it feels calm and
soothing.
10. Wave Speed
Distance
Time
How fast a wave moves from one place to another,
measured in meters per second (m/s) or kilometers
per hour (km/h)
If a wave travels 10 meters in 2
seconds, its speed would be 5
meters per second.
Speed=
10m
2s
5s=
13. Solve the following:
1. If the frequency of the wave is 25
Hz and a speed of 200 m/s what
would be the wavelength?
14. 1. If the frequency of the wave is 25 Hz
and a speed of 200 m/s what would be
the wavelength?
Given: f: 25Hz v= 200m/s
Formula: f= v/ λ
= 200m/s ÷ 25s
= 8m
Solve the following:
15. 2. A wave of wavelength 1.5 m
travels down a rope at a speed of 6
m/s. What is the frequency of the
wave?
Solve the following:
16. 3. A wave of wavelength 1.5 m travels down
a rope at a speed of 6 m/s. What is the
frequency of the wave?
Given: λ: 1.5m v= 6m/s
Formula: f= v/ λ
= 6m/s ÷ 1.5m
= 4 Hz
Solve the following:
17. 3. A vibration of frequency 5 Hz
sends a wave of wavelength 0.8 m
down a rope. What is the speed of
the wave?
Solve the following:
18. 3. A vibration of frequency 5 Hz sends a
wave of wavelength 0.6 m down a rope.
What is the speed of the wave?
Given: f = 5Hz λ=0.6m
Formula: v = f λ
= 5Hz x 0.6m
= 3.5 m/s
Solve the following:
20. 1. v= ? λ = 8 m ƒ = 20 Hz
2. λ = ? v = 50 m/s ƒ = 25 Hz
3. ƒ = ? v = 50 m/s λ = 10 m
4. v = ? λ = 1 m ƒ = 345 Hz
5. λ = ? v = 100 m/s ƒ = 3 Hz
6. ƒ = ? v = 120 m/s λ = 3 m
7. v = ? λ = 3 m and ƒ = 10 Hz
8. λ = ? f = 27 Hz v= 46 m/s
9. v = ? λ = 100m f = 5 Hz
10. ƒ = ? v = 350 λ = 10
21. SUMMARY
• 2 Categories of Waves are Electromagnetic Waves and Mechanical Waves
• Electromagnetic waves are waves that are capable of transmitting energy through vacuum
• Mechanical waves require a medium to transport their energy from one location to another.
• A sound wave is an example of a mechanical wave. Sound waves are incapable of traveling through a vacuum.
• All light waves are examples of electromagnetic waves..
• Electromagnetic waves are produced by the vibration of charged particles.
• Slinky waves, water waves, stadium waves, and jump rope waves are other examples of mechanical waves; each requires some
medium to exist.
• Properties of Waves are wavelength, wave speed and frequency.
• Wavelength- Distance between two successive crest or troughs of transverse wave. The symbol is λ (lamda) and is measured in
meters.
• Frequency- Number of complete cycles or waves that occur in a given amount of time, measured in hertz. Hz = s-1 (also written as Hz =
1/s).
• Wave speed- How fast a wave moves from one place to another, measured in meters per second (m/s) or kilometers per hour (km/h
22.
23. 1. What is the v if λ = 8 m and ƒ = 20 Hz?
2. What is the λ if v = 50 m/s and ƒ = 25 Hz?
3. What is the ƒ if v = 50 m/s and λ = 10 m?
4. What is the v if λ = 1 m and ƒ = 345 Hz?
5. What is the λ if v = 100 m/s and ƒ = 3 Hz?
6. What is the ƒ if v = 120 m/s and λ = 3 m?
7. What is the v if λ = 3 m and ƒ = 10 Hz?
8. What is the λ if f = 27 Hz and v= 46 m/s?
9. What is the v if λ = 100m and f = 5 Hz?
10.What is the ƒ if v = 350 and λ = 10?
Notes de l'éditeur
Disturbances that require a medium to propagate are classified as mechanical waves. These waves are not capable of transmitting energy through vacuum. Common examples of mechanical waves are sound waves, water waves, and a wave traveling along a string.
Ex. Radio waves, light waves, infrared waves, ultraviolet waves, x-rays, gamma rays
Unlike mechanical waves, EM waves can propagate even without a medium. These waves are produced by accelerating electric charges such as the vibration of electrons within atoms on the sun’s surface.
Is the number of waves that pass a given point in a certain amount of time.
For example, 50 km/hr (31 mph) describes the speed at which a car is traveling along a road, while 50 km/hr west describes the velocity at which it is traveling.
Speed refers to an object's change in distance with respect to time, whereas velocity refers to an object's change in displacement with respect to time.