P3 Waves - electromagnetic spectrum

What are electromagnetic waves?

transverse waves that don’t need a medium

Name all the waves in the electromagnetic spectrum

radio, microwave, infrared, visible, ultraviolet, X-ray, gamma

Order the electromagnetic spectrum in order of wavelength (shortest to longest)

gamma rays, X-rays, ultraviolet, visible light, infrared, microwaves, and radio waves

Order the electromagnetic spectrum in order of frequency (shortest to longest)

radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays

What is the speed like for all electromagnetic waves?

all waves travel with the same high speed in a vacuum

What is the speed of electromagnetic waves in a vacuum? +what is it the same as

3.0 × 10⁸ m/s and is approximately the same in air

What is the relationship between wavelength and frequency?

as wavelength decreases, frequency must increase

What is radio waves used for?

radio and television transmissions, radar

Why are radio waves used for radio and television transmissions, radar?

they have a long wavelength, travel long distances and are reflected by the ionosphere.

What is microwaves used for?

satellite television, mobile (cell) phone, microwave ovens

Why are microwaves used for satellite television, mobile (cell) phone, microwave ovens?

they pass through the ionosphere and penetrate deep into food, heating it up

What is infrared used for?

remote controllers for televisions, thermal imaging

Why is infrared used for remote controllers for televisions, thermal imaging?

carries signals over short distances and detects heat differences in objects

What is visible light used for?

vision, photography

Why is visible light used for vision, photography?

can be detected by our eyes and captured by cameras to produce images

What is ultraviolet used for?

detecting fake bank notes, tanning bed

Why is ultraviolet used for detecting fake bank notes, tanning beds?

makes special security markings glow, revealing hidden patterns on fake bank notes, stimulates skin to produce vitamin D, causing tanning

What are X-rays used for?

medical scanning, security scanners

Why are X-rays used for medical scanning, security scanners?

they can penetrate through soft tissue easily but are absorbed by dense materials like bone or metal, creating clear images.

What are gamma rays used for?

detection of cancer and its treatment

Why are gamma rays used for detection of cancer and its treatment?

they penetrate tissues deeply and kill cancer cells effectively.

What is harmful effect of ultraviolet on people of excessive exposure?

damage to surface cells and eyes, leading to skin cancer and eye conditions

What is harmful effect of X-rays and gamma rays of excessive exposure?

mutations that could lead to cancer or damage to cells in the body

What are sound waves?

longitudinal waves created by vibrating sources. a medium is needed to transmit sound waves.

How do sound waves pass through the air?

as the wave passes through the air, it produces a series of compressions and rarefactions that move away from the source of the sound in all directions, spreading the sound wave outwards

What are compressions?

regions of higher pressure due to particles being closer together

What are rarefactions?

regions of lower pressure due to particles being spread further apart

How is amplitude increased?

larger vibrations

How does changing amplitude affect the loudness and pitch of sound waves?

The greater the amplitude of a sound wave, the louder it is.

How is frequency increased?

faster vibrations

How does changing frequency affect the loudness and pitch of sound waves?

The greater the frequency of a sound wave, the higher its pitch.

How to determine the speed of sound in air?

make a noise at a known, large distance from a solid wall and record the time for the echo to be heard, then use speed =distance/time, taking into account the fact that the sound had to go there and back.

What is an echo?

the reflection of a sound wave

Does sound travel faster in solids, liquids or gases?

sound travels faster in solids than in liquids and faster in liquids than in gases

Why do sound travel faster in in solids than in liquids and faster in liquids than in gases?

Solids: Strong intermolecular forces and closely packed particles allow efficient energy transfer.

Liquids: Particles are less tightly packed than in solids, leading to slower sound propagation.

Gases: Particles are far apart, resulting in the slowest sound transmission.

What is the approximate range of frequencies audible to humans?

20 Hz to 20000 Hz

What is an ultrasound?

sound with a frequency higher than 20kHz/20000 Hz

How does an ultrasound work?

-When ultrasound reaches a boundary between two media it is partially reflected back. The remainder of the waves continue to pass through.

-A transceiver can emit ultrasound and record the reflected waves to find the distance of things below the surface.