AKS 9b and d - EM and Mechanical Waves/Speed of waves in media

​Electromagnetic vs. Mechanical Waves

By Ms. Brown

Multiple Choice

Which of the following EM waves has the lowest energy?

• Radio Waves

• Microwaves

• Infrared

Multiple Choice

As the frequency of an electromagnetic wave increases, the wave....

• gets stronger

• gets weaker

• does not change

Multiple Choice

Which has the SHORTEST wavelength and, therefore, the highest frequency/most energy

• Radio waves
• Ultraviolet Rays
• Gamma Rays
• X-rays

Multiple Choice

Which section of the spectrum is the ONLY one we can see?

• X-rays
• Visible Light
• Gamma Rays
• Ultraviolet Rays

Multiple Choice

Select the correct order of waves on the EMS from the longest wavelength to the shortest wavelength

• Radio, Micro, Infra, Visible, Ultra, X-ray, Gamma
• Gamma, X-ray, Ultra, Vis, Infra, Micro, Radio
• Vis, Micro, Infra, Ultra, X-ray, Gamma, Radio
• Micro, Radio, Vis, Infra, Ultra, X-ray, Gamma

Multiple Choice

How are electromagnetic waves different from other waves? 

• They have very short wavelengths 
• They transmit energy instead of matter 
• They can travel through empty space
• They can change direction by reflection 

Multiple Choice

Which of the following electromagnetic waves has the lowest energy?

• gamma ray
• infrared wave
• visible light wave
• microwave

Reorder

Reorder the following from longest (1) wavelength to shortest (5)

• Red

• Orange

• Yellow

• Blue

• Violet

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

Reorder

Reorder the following from highest (1) frequency to lowest (5)

• Red

• Orange

• Yellow

• Blue

• Violet

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

​Electromagnetic waves

• ​All electromagnetic waves travels at the speed of light 3.0 x 10⁸ m/s in a VACUUM. However, they travels at different speeds when traveling through matter.

• They travel fastest in less dense medium, so fastest in gases and slowest in solids.

• Ex: Radio waves, Microwaves, Infrared, Visible Light, Ultraviolet, X-rays, and Gamma Ray.

Multiple Choice

EM waves  

• Must travel through a vacuum
• Can travel through a medium or a vacuum
• Are the same type of wave as mechanical waves
• Can only travel through a vacuum

Reorder

Reorder from fastest (1) to slowest (2) for the speed of Electromagnetic (light waves)

• Solid

• Liquid

• Gas

• Space

1

2

3

4

• 1
• 2
• 3
• 4

​Mechanical waves

• ​These require a medium for the vibrations to travel and so cannot travel through space (vacuum)

• ​

• ​May either move as transverse or longitudinal waves.

• ​

• ​Ex. sound, water wave, slinky,

​​Mechanical waves

• ​The speed at which they travel depends on either the type of wave or the medium they are in.

• ​

• ​They travel fastest in more dense medium. Therefore, they move fastest in solids and slowest in gases.

• ​

• ​Generally, these have longer wavelengths than electromagnetic waves.

Multiple Choice

What type of wave is a sound wave?

• Transverse wave

• Longitudinal wave

• Electromagnetic wave

• Surface wave

Multiple Choice

Explain why sound waves cannot travel through a vacuum.

• Sound waves require a medium to transfer energy

• Sound waves are too weak to travel in a vacuum

• Sound waves are absorbed by the vacuum

• Sound waves are reflected by the vacuum

Multiple Choice

The pitch of a sound is related to the...

• amplitude of the sound wave

• frequency of the sound wave

• speed of a sound wave

• reflection of a sound wave

Multiple Choice

Which statement can be made based on these data?

• Sound waves are slowest in liquids and fastest in gases.
• Sound waves are fastest in solids and slowest in gases.
• Speed of a sound wave increases from one medium to another.
• Speed of a sound wave decreases from one medium to another.