Electromagnetic Waves

An ultraviolet wave traveling through a vacuum has a wavelength of 4.0 × 10-7 m. The wave's frequency, written in scientific notation to two significant figures, is ( )× 10^14 Hz.

7.5

An infrared wave traveling through a vacuum has a frequency of 4.0 × 1014 Hz. What is the wave's wavelength? 7.5 × 10^7 m 7.5 × 10^-7 m 1.2 × 10^14 m 1.2 × 10^-14 m

7.5 × 10-7 m

As the frequency of electromagnetic waves increases, what happens to the wavelength? It increases. It decreases. It fluctuates. It remains constant.

It decreases.

Explain why the speed of light is lower than3.0 × 108 m/s as it goes through different media.

Sample Response: In a vacuum, there are no atoms or particles that interfere with the path of light. However, in other media, the speed of light is lower than 3.0 × 108 m/s because the wave is continuously absorbed and re-emitted by each atom in its path. The differences in speed are due to the composition of the medium and the density of the particles in the medium.

What do all electromagnetic waves have in common? They can travel at the speed of light. They have the same wavelengths. They travel only through matter. They have nonmoving magnetic fields.

They can travel at the speed of light.

Which best describes electromagnetic waves moving from gamma rays to radio waves along the electromagnetic spectrum? Wavelength and frequency decrease. Wavelength and frequency increase. Wavelength increases, and frequency decreases. Wavelength decreases, and frequency increases.

Wavelength increases, and frequency decreases.

Which part of visible light transfers the most energy? red blue green yellow

blue

Remote controls rely on ( )waves to carry signals and transmit information over short distances.

infrared

Which are electromagnetic waves? Check all that apply. earthquake waves infrared waves ocean waves radio waves ultraviolet waves

infrared waves radio waves ultraviolet waves

When caring for wounds, doctors need to make sure wounds are not infected by bacteria. Which electromagnetic wave would doctors most likely use for this purpose? gamma rays ultraviolet waves visible light X-rays

ultraviolet waves

Which two electromagnetic waves are useful for diagnosing illnesses? X-rays and radio waves microwaves and gamma rays gamma rays and visible light radio waves and ultraviolet waves

X-rays and radio waves

Isla made a diagram to compare X-rays and radio waves. What should Isla write in the areas marked A, B, and C? A: Has a longer wavelengthB: Can travel only through matterC: Has a higher frequency A: Has a higher frequencyB: Can travel only through matterC: Has a longer wavelength A: Has a higher frequencyB: Travels at the same speedC: Has a longer wavelength A: Has a longer wavelengthB: Travels at the same speedC: Has a higher frequency

A: Has a higher frequency B: Travels at the same speed C: Has a longer wavelength

Which describes the relationship between the frequency, wavelength, and speed of a wave as the wave travels through different media? As speed changes, wavelength changes and frequency remains constant. As speed changes, frequency changes and wavelength remains constant. As speed changes, wavelength and frequency change. As speed changes, wavelength and frequency remain constant.

As speed changes, wavelength changes and frequency remains constant.

Explain how electromagnetic waves are produced

Sample Response: The source of electromagnetic waves are charged particles that begin to oscillate when acted upon by a disturbance. These oscillating particles create an oscillating magnetic field. The oscillating magnetic field then creates an oscillating electric field, and an oscillating electric field in turn creates an oscillating magnetic field.

Wave Y and wave Z are two types of electromagnetic waves traveling through a vacuum. Suppose the frequency of wave Y is about three times greater than the frequency of wave Z. Which best compares the energy transferred by the two waves? 1. It is the same for each wave because the amount of energy transferred is constant in all types of electromagnetic waves. 2. Wave Y transfers about one-third the amount of energy as wave Z because energy and frequency have an inverse relationship. 3. Wave Y transfers about three times the amount of energy as wave Z because energy and frequency have a direct relationship. 4. It is zero for each wave because when waves travel through a vacuum, they do not transfer energy.

Wave Y transfers about three times the amount of energy as wave Z because energy and frequency have a direct relationship.

Which lists the waves in order of frequency, from highest to lowest? X-rays, gamma rays, ultraviolet radio waves, visible light, X-rays ultraviolet, microwaves, gamma rays visible light, infrared, microwaves

visible light, infrared, microwaves