Light Energy

The medium through which a mechanical wave passes can be a solid, a liquid, or a gas. Properties of a wave might change when it moves from one medium to another. What happens to the speed of a wave when it moves from a gas to a solid?

• It speeds up

• It slows down

• It remains the same

• It speeds up and then slows down

Suppose a mechanical wave is traveling through medium A. When the wave enters medium B, it speeds up. Which of the following statements is true about medium A and medium B?

• Medium A is a solid and medium B is a gas

• Medium A is a liquid and medium B is a solid

• Medium A is a gas and medium B is a vacuum

• Medium A is a vacuum and medium B is a liquid

Through which medium does a mechanical wave travel most quickly?

• Solid

• Liquid

• Less dense gas

• Very dense gas

What can Sara observe when a mechanical wave travels through ice into water vapor?

• The wavelength increases when it enters the water vapor

• The period increases when it enters the water vapor

• It travels faster through the ice than it does through the water vapor

• It travels faster through the water vapor than it does through the ice

Through which of these media do sound waves travel most slowly?

• Iron

• Wood

• Water

• Cold air

The energy generated by the sun travels to Earth as electromagnetic waves of varying lengths. Which statement describes an electromagnetic wave with a long wavelength?

• It has a high frequency and low energy

• It has a high frequency and high energy

• It has a low frequency and can travel through a vacuum

• It has a low frequency and needs a medium to travel through

Great amounts of electromagnetic energy from our sun and other bodies in space travel through space. Which is a logical conclusion about these electromagnetic waves?

• Their energy must be very low

• Their frequency must be very low

• Their wavelengths must be very short

• These waves can travel without a medium

The visible part of the electromagnetic spectrum consists of the colors that we see in a rainbow. Each color we

see corresponds to a different wavelength of light. Which color of visible light has the shortest wavelength?

• Red

• Green

• Violet

• Yellow

Our eyes detect light that lies only within a small region of the electromagnetic spectrum. This region is called

visible light. Which of these statements describes the visible spectrum of light as seen by the human eye?

• The lowest frequency appears red, and the highest frequency appears violet.

• The lowest frequency appears green, and the highest frequency appears red.

• The lowest frequency appears blue, and the highest frequency appears orange.

• The lowest frequency appears yellow, and the highest frequency appears green.

Which of the waves listed below has the highest frequency?

• Radio waves

• X-ray aves

• Infrared waves

• Ultraviolet waves