Question

8
multiple choice 5 points
what property of electromagnetic waves makes it possible to use these waves to transmit information between a space shuttle and nasa mission control centers on the ground?
electromagnetic waves are transverse waves.
electromagnetic waves have very low velocity.
electromagnetic waves are all visible to human eyes.
electromagnetic waves can travel through a vacuum.
9
multiple choice 5 points
an echo is strong evidence that sound can be
amplified
diffracted
dispersed
reflected
10
multiple choice 5 points
which waves require a material medium for transmission?
light waves
radio waves
sound waves
microwaves

Explanation:

• Question 8:
• Electromagnetic waves can travel through a vacuum. Space is a vacuum, so this property allows communication between the space shuttle (in space) and NASA mission control centers (on the ground).
• Electromagnetic waves being transverse waves (a wave property) does not directly relate to transmission in a vacuum.
• Electromagnetic waves have a high velocity (speed of light in vacuum \(c = 3\times10^{8}\space m/s\)), not a low velocity.
• Only a small part of the electromagnetic spectrum (visible light) is visible to human eyes.
• Question 9:
• An echo is a sound that is heard again because the sound wave is reflected off a surface (e.g., a wall in a canyon).
• Amplification would make the sound louder but not create an echo.
• Diffraction is the bending of waves around obstacles, which is not related to an echo.
• Dispersion is the separation of waves into different components (e.g., white light into colors), which is not relevant to an echo.
• Question 10:
• Sound waves require a material medium (solid, liquid, or gas) for transmission. They propagate by causing the particles of the medium to vibrate.
• Light waves, radio waves, and microwaves are electromagnetic waves and can travel through a vacuum (they do not require a material medium for transmission).

Answer:

• Question 8: Electromagnetic waves can travel through a vacuum.
• Question 9: reflected
• Question 10: sound waves