Unit 4 Summative Practice

Which of the following statements about electromagnetic and mechanical waves is true?

• Electromagnetic waves must travel through a medium, but mechanical waves do not require a medium.

• Electromagnetic waves travel mostly through matter, and mechanical waves travel mostly through a vacuum.

• Mechanical waves must travel through a medium, but electromagnetic waves do not require a medium.

• Mechanical waves sometimes travel through a vacuum, and electromagnetic waves sometimes travel through matter.

Which of the following statements is true with regard to transverse and longitudinal waves?

• Both transverse waves and longitudinal waves have motion parallel to velocity.

• Transverse waves have motion parallel to velocity, while longitudinal waves have motion perpendicular to velocity.

• Transverse waves have motion perpendicular to velocity, while longitudinal waves have motion parallel to velocity.

• Both transverse waves and longitudinal waves have motion perpendicular to velocity.

Which of the following correctly shows the part of the wave that represents the wavelength?

• 
• 
• 
• 

Which of the following shows the correct order of the electromagnetic spectrum, from shortest wavelength to longest?

• gamma ray → X-ray → ultraviolet → visible → infrared →

       microwave → radio

• radio → microwave → infrared → visible → ultraviolet →   

       X-ray → gamma ray

• visible → infrared → ultraviolet → X-ray → gamma ray →

       radio → microwave

• microwave → X-ray → gamma ray → ultraviolet → visible

       → radio → infrared

Which wavelengths of light can human eyes detect?

• ultraviolet waves

• infrared waves

• visible waves

• X-ray waves

Directions: The picture below shows three light rays from the Sun that traveled toward Earth. Use the picture to answer any questions that follow. What happened to light ray Y?

• It was absorbed by the carbon dioxide molecules and made  

       oxygen.

• It was reflected by the ground and headed back into space.

• It was refracted by the atmosphere due to changes in air

       density.

• It was scattered by the clouds due to a change in temperature.

What is the difference between a reflected and a diffracted sound wave?

• A diffracted sound wave bounces back to the place of origin.

      A reflected sound wave changes direction as it passes through

      an opening.

• A diffracted sound wave bounces back to the place of origin.

       A reflected sound wave is absorbed as it passes through an

       opening.

• A reflected sound wave bounces back to the place of origin.

       A diffracted sound wave changes direction as it passes

       through an opening.

• A reflected sound wave is absorbed by the medium. A

       diffracted sound wave changes direction as it passes through  

       an opening.

The graphic shows a red light shining on objects Q and R. Object Q appears to be black, and object R appears to be red. Which of the following is correct?

• Object Q refracts red light, and object R diffracts red light.

• Object Q diffracts red light, and object R refracts red light.

• Object Q reflects red light, and object R absorbs red light.

• Object Q absorbs red light, and object R reflects red light.

What is the name given to the substance through which a wave travels?

• crest

• medium

• trough

• frequency

The data shows the speed of sound through air and sea water at 21°C.  How does the speed of sound in seawater compare to the speed of sound in air?

• The speed of sound is slower in sea water because the

       molecules in sea water are closer to each other and less

       dense.

• The speed of sound is faster in sea water because the  

       molecules in sea water are closer to each other and less  

       dense.

• The speed of sound is faster in sea water because the

       molecules in sea water are closer to each other and more

       dense.

• The speed of sound is slower in sea water because the

       molecules in sea water are closer to each other and more

       dense.