Physics Unit 5 Electromagnetic Spectrum - Parson's Scienceparsonscience.weebly.com/.../2/3/0/3/23031306/_waves_light_sound_n… · Wave • A rhythmic disturbance that transfers energy

Physics Unit 5Waves – Light & Sound

Wave• A rhythmic disturbance that transfers

energy through matter and/or a vacuum• Material a wave travels through is called the

medium• 2 types of waves:

1. Transverse2. Compressional (Longitudinal)

Transverse• Matter in the wave moves at right angles to

the direction of the wave front

mid line (resting position)

Crest

Trough

amplitude

Wavelength (λ)

Examples: gamma radiation, x-ray, UV, visible light, infrared, microwave, radio, TV, water

Compressional (Longitudinal)• Matter moves in the same direction as

(along with) the wave frontcompression

rarefaction

λ

Example: sound

Transverse & Compressional• Amplitude (A)

-determined by amount of energy• Wavelength (λ)

-determined by the wave frequency• Frequency (f)

-number of waves per second-measured in hertz (Hz)

Transverse & Compressional• Velocity (v)

-v = λf-varies based on temperature, what it is traveling thru-stays the same in a given medium

• velocity of light (all transverse waves)- 300,000,000 m/s

• velocity of sound (longitudinal waves)-330 m/s

Frequency Comparisons• Transverse • Longitudinal

High frequency-purple light

Low frequency-red light

High frequency-High pitch

low frequency-low pitch

Amplitude Comparisons• Transverse • Longitudinal

High amplitude-bright light

Low amplitude-dim light

High amplitude-loud

low amplitude-quiet

Transverse vs. Longitudinal

Check upWhich has a

longer λ?-A

Which has higher frequency?

-BWhich has higher

amplitude?-both same

Physics Unit 5Electromagnetic Spectrum

Electromagnetic Spectrum• Transverse waves that go in order of

increasing frequencies (decreasing wavelengths)

• some wave frequencies overlap

8._______

7._______

6._______

5._______

4._______

3._______

2._______

1._______

9._______ frequency10._______ wavelength


13._______ _______ _______ _______ _______ _______

Electromagnetic Spectrum

8._______

7._______

6._______

5._______

4._______

3._______

2._______

1.TV



13._______ _______ _______ _______ _______ _______


8._______

7._______

6._______

5._______

4._______

3._______

2.Radio

1.TV



13._______ _______ _______ _______ _______ _______


8._______

7._______

6._______

5._______

4._______

3.microwaves

2.Radio

1.TV



13._______ _______ _______ _______ _______ _______


8._______

7._______

6._______

5._______

4.infrared

3.microwaves

2.Radio

1.TV



13._______ _______ _______ _______ _______ _______


8._______

7._______

6._______

5.visible light

4.infrared

3.microwaves

2.Radio

1.TV



13._______ _______ _______ _______ _______ _______


8._______

7._______

6._______

5.visible light

4.infrared

3.microwaves

2.Radio

1.TV



13.red _______ _______ _______ _______ _______


8._______

7._______

6._______

5.visible light

4.infrared

3.microwaves

2.Radio

1.TV



13.red orange _______ _______ _______ _______


8._______

7._______

6._______

5.visible light

4.infrared

3.microwaves

2.Radio

1.TV



13.red orange yellow _______ _______ _______


8._______

7._______

6._______

5.visible light

4.infrared

3.microwaves

2.Radio

1.TV



13.red orange yellow green _______ _______


8._______

7._______

6._______

5.visible light

4.infrared

3.microwaves

2.Radio

1.TV



13.red orange yellow green blue _______


8._______

7._______

6._______

5.visible light

4.infrared

3.microwaves

2.Radio

1.TV



13.red orange yellow green blue violet


8._______

7._______

6.ultraviolet

5.visible light

4.infrared

3.microwaves

2.Radio

1.TV





8._______

7.x-ray

6.ultraviolet

5.visible light

4.infrared

3.microwaves

2.Radio

1.TV





8.Gamma

7.x-ray

6.ultraviolet

5.visible light

4.infrared

3.microwaves

2.Radio

1.TV





8.Gamma

7.x-ray

6.ultraviolet

5.visible light

4.infrared

3.microwaves

2.Radio

1.TV

9.Low frequency10._______ wavelength




8.Gamma

7.x-ray

6.ultraviolet

5.visible light

4.infrared

3.microwaves

2.Radio

1.TV

9.Low frequency10._______ wavelength

11.High frequency12._______ wavelength



8.Gamma

7.x-ray

6.ultraviolet

5.visible light

4.infrared

3.microwaves

2.Radio

1.TV

9.Low frequency10.Long wavelength

11.High frequency12._______ wavelength



8.Gamma

7.x-ray

6.ultraviolet

5.visible light

4.infrared

3.microwaves

2.Radio

1.TV

9.Low frequency10.Long wavelength

11.High frequency12.Short wavelength



Exploring Electromagnetic Spectrum

Doppler Effect

• The apparent shift in frequency caused by the movement of the sound source or the movement of the observer.

• When the waves get crunched together (in front of the moving sound) the frequency of the wave is increased and the sound is high in pitch.

• When the waves get spread apart (behind the moving sound) the frequency of the wave is decreased and the sound is low in pitch.

Doppler Effect

High pitch

Low pitch

Doppler Effect

• Used in police radar to determine the speed of an oncoming car.

• Used by meteorologists to determine the size and speed of an approaching frontal system.

• Explains the sound you hear when listening to a Nascar race!

Waves• Since waves travel at fast speeds in straight

lines, eventually they will run into something.

• Sometimes they run into things.• Sometimes they run into other waves.

1. Reflection

• If a wave strikes an object and bounces off, we say that it has reflected.

Law of Reflection

• The angle of incidence is always equal to the angle of reflection.

Law of Reflection

• The law holds true even if the reflective surface is not flat.

Reflection• An image formed in a concave or convex

mirror is distorted, but the angles of incidence and reflection are always equal. (Think about your image in a fun-house mirror!)

2. Refraction

• If a wave strikes an object and passes through it, we say it has been refracted.

• When a wave passes from one medium into another, its speed changes. When a wave’s speed changes, it changes direction as well.

When a wave is slowed, it bends toward the normal line. When a wave speeds up, it bends away from the normal line.

Refraction

• Different media cause waves to bend different amounts.

• The amount that a medium bends waves passing through it is called its index of refraction.

Refraction

This pencil appears to be bent because light traveling from the pencil to your eye is bent at the surface of the water.

Refraction

It is difficult to dive for coins in a pool or spear fish in a lake because the light traveling from the object to your eye is bent at the surface of the water, changing its apparent location.

RefractionDiamond has a high index of refraction. Light is bend sharply as it passes through diamond. This is why we can often see many different colors coming off of a diamond. Some light is also reflected off the surface of the diamond. This is sometimes called ‘sparkle.’

3. Absorption• If a wave strikes an object and does not

reflect off the surface or pass through, it is absorbed.

• In this case, the wave energy is converted into heat and the temperature of the object increases.

• Dark colors absorb more energy than light colors.

Reflection• Wave bounces off an object

4. Incident Wave

1. ∠ incidence2. Normal line

3. ∠ reflection

5. Reflected Wave

Law of Reflection: ∠ incidence = ∠ reflection

Refraction• Waves pass through the medium

air

glasssurface

9. Normal line

8. Incident wave

10. refracted wave

7. ∠ Incidence

11. ∠ Refraction

When a wave slows down, it bends toward the normal line

Interference

Constructive1.

2. Destructive

Interference

Destructive3.

4. Constructive

Physics Unit 5 Electromagnetic Spectrum - Parson's Scienceparsonscience.weebly.com/.../2/3/0/3/23031306/_waves_light_sound_n… · Wave • A rhythmic disturbance that transfers energy

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