EM Spectrum

What are waves?

Waves are vibrations that transfer energy from one place to another.

What is never transferred by waves?

Matter.

How do particles move in transverse waves?

At right angles to the direction of the wave.

How do particles move in longitudinal waves?

In the direction that the wave is travelling.

Give one example of a transverse wave.

Light waves, seismic waves or water waves.

Give one example of a longitudinal wave.

Sound waves or seismic waves.

Define wavelength.

The distance between peaks or troughs in a wave.

What two things do waves transfer?

Energy and information.

Define refraction and explain how it happens.

Refraction is the bending of waves as they pass through a different medium. It occurs because they travel at different speeds in different materials.

Describe the properties of red light.

It has the longest wavelength, the lowest frequency and the lowest energy.

Describe the properties of violet light.

It has the shortest wavelength, the highest frequency and the highest energy.

Do black objects absorb or reflect all colours?

Absorb

Do white objects absorb or reflect all colours?

Reflect

How fast do EM spectrum waves travel in a vacuum?

300,000,000 m/s

Which wave has the lowest energy and frequency, but the longest wavelength?

Radio waves.

Which wave has the highest energy and frequency, but the shortest wavelength?

Gamma rays.

List the EM spectrum from lowest to highest energy.

Radio waves, microwaves, infrared radiation, visible light, ultraviolet, x-rays, gamma rays.

Name a use for infrared radiation.

Thermal imaging or TV remotes.

Name a use for radio waves.

Communication.

Name a use for microwaves.

Cooking or communication.

Name a use for visible light.

Seeing or fibre optic cables.

Name a use for ultraviolet.

Detecting forgery, tanning beds or sterilising drinking water.

Name a use for x-rays.

Medical imaging and airport scans.

Name a use for gamma rays.

Detecting and curing cancer.

Define frequency.

The number of waves passing a point per second.

Define period.

The time it takes for a wave to pass a point.

What is the simpler calculation for wave speed?

s = d/t , or wave speed (m/s) = distance (m) / time (s)

What is the more complicated calculation for wave speed?

s = f x λ , or wave speed (m/s) = frequency (Hz) x wavelength (m)

How do our eyes allow us to see things?

Light reflects off of objects and into our eyes.

How do we communicate with spacecrafts and other far away things?

With satellites and radio waves.

How are radio waves produced?

By variations in current and voltage, called oscillations.

Describe how easy or difficult it is for x-rays to pass through the body.

They can pass through muscle and fat easily but bone will absorb more x-rays.