Question

Sound waves travel at about 259 meters per second through gaseous carbon dioxide. They travel at about 1,162 meters per second through liquid ethanol. And they travel at 1,960 meters per second though solid lead. Which of the following statements about electromagnetic waves is true? A. Electromagnetic waves travel faster than sound waves through all media. B. Electromagnetic waves travel faster than sound waves through gases but not through liquids. C. Electromagnetic waves travel faster than sound waves through liquids but not through solids. D. Sound waves travel faster than electromagnetic waves through all media.

Answer 1

The correct answer is
A. Electromagnetic waves travel faster than sound waves through all media.

In fact, electromagnetic waves in vacuum travel at the speed of light:

`c=3 \cdot 10^8 m/s`
which is a huge value compared to the value of the speed of sound through all media listed in the problem. In a medium, the speed of the electromagnetic waves is slightly reduced compared to c, but still much greater than the value of the speed of sound.