Understanding Light and Sound Waves

Which part of the electromagnetic spectrum is visible to the human eye?

• Ultraviolet rays

• Visible light

• Gamma rays

• X-rays

Answer explanation

The part of the electromagnetic spectrum that is visible to the human eye is called visible light. It encompasses wavelengths from approximately 400 to 700 nanometers, allowing us to see colors like red, green, and blue.

Why do we see a red apple as red?

• The apple absorbs red light and reflects all other colors

• The apple emits its own red light

• The apple reflects red light and absorbs all other colors

• The apple transmits red light through it

Answer explanation

We see a red apple as red because it reflects red light while absorbing all other colors. This selective reflection is why our eyes perceive the apple as red.

What happens when light passes through a prism?

• It gets absorbed

• It reflects all wavelengths equally

• It bends and separates into different colors

• It becomes a longitudinal wave

Answer explanation

When light passes through a prism, it bends due to refraction and separates into different colors, creating a spectrum. This occurs because different wavelengths of light are refracted by different amounts.

Which feature is present in both sound and light waves?

• The highest point in a wave

• A region where particles are far apart

• The height of a wave, showing its energy

• The lowest point in a wave

Answer explanation

The highest point in a wave, known as the crest, is a common feature in both sound and light waves. It represents the maximum displacement from the rest position, indicating the wave's energy.

What is something that both light and sound waves share?

• They both need matter to travel.

• They both start due to vibrations.

• They both move in the same way.

• They have the same speed.

Answer explanation

Both light and sound waves originate from vibrations. Light waves are produced by oscillating electric and magnetic fields, while sound waves result from vibrating objects. Thus, they share this common characteristic.

Which type of wave moves at the highest speed?

• Waves in the ocean

• Waves that carry sound

• Waves from earthquakes

• Waves that include light and radio signals

Answer explanation

Waves that include light and radio signals travel at the speed of light, approximately 299,792 kilometers per second, making them the fastest type of wave compared to ocean waves, sound waves, and seismic waves.

Why do certain colors, like pink, not appear as part of the electromagnetic spectrum?

• They don’t actually exist.

• They result from the blending of multiple wavelengths.

• They are hidden by other colors.

• They are created by our eyes.

Answer explanation

Colors like pink do not appear in the electromagnetic spectrum because they are not single wavelengths. Instead, they result from the blending of multiple wavelengths, which our brains interpret as a distinct color.

What allows an object, like an apple, to appear red to our eyes?

• It absorbs red light and lets the other colors pass through.

• It creates its own red light.

• It reflects red light while absorbing the other colors.

• It reflects all colors except red.

Answer explanation

An apple appears red because it reflects red light while absorbing other colors. This selective reflection is what allows our eyes to perceive the apple as red.

Which statement describes something that is true about both sound and light energy?

• Both need air to move.

• Both transfer energy in the form of waves.

• Both move through space the same way.

• Both can travel at the same rate of speed.

Answer explanation

The correct statement is that both sound and light energy transfer energy in the form of waves. Sound travels as mechanical waves through a medium, while light travels as electromagnetic waves, demonstrating their wave nature.

Which part of the electromagnetic spectrum can people see?

• Ultraviolet waves

• Infrared waves

• X-rays

• Visible light

Answer explanation

People can see visible light, which is the portion of the electromagnetic spectrum that is detectable by the human eye. Ultraviolet waves, infrared waves, and X-rays are not visible to us.