Question

Read the passage and answer the following question(s).



Speed of Light and Sound Waves



A student investigates the speed of waves through different materials. The student knows that sound is a mechanical wave that travels on longitudinal waves, while light is an electromagnetic radiation that travels on a transverse wave. A sound and light wave are shown.



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The student measures the speed of sound as it passes through three different materials. The type of material, density of the material, and speed of sound as it passes through each material are recorded in the data table.


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The student then measures the speed of light through the same materials and records the data in the table.


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The following question has two parts. First, answer Part A. Then, answer Part B.



Part A:



A student investigates the speed of sound and light through four new substances.



The data table shows the densities of each substance.



Substance
Density

(g/cm3)

A 0.364
B 1.40
C 0.79
D 1.26




Which statement BEST compares the speed of light and sound through the substances?




Light will travel faster in Substance D than in Substance A.


Light will travel faster in Substance C than in Substance D.


Sound will travel faster in Substance C than in Substance B.


Sound will travel faster in Substance A than in Substance B.



Part B:



Which statement BEST supports the choice in Part A?


The particles in Substance A are farther apart than in Substance B.


The particles in Substance A are farther apart than in Substance D.


The particles in Substance C are farther apart than in Substance B.


The particles in Substance C are farther apart than in Substance D.

Answer 1

Part A: Light will travel faster in Substance C than in Substance D.

Reason: C has lower density (0.79) than D (1.26), and light travels faster in less dense (less optically dense) media.

Part B: The particles in Substance C are farther apart than in Substance D.