3.11 The Order of the Electromagnetic Spectrum

The Diagram bellow clearly shows the 7 parts of the E-M spectrum in order of decreasing wavelength, from left to right

An easy way to remember the order is with a mnemonic

For example for the E-M spectrum (RMIVUXG)

you could have:

Reading Music Is Very Unsatisfactory for Xylophones and Glockenspiels

and for the visible portion of the spectrum (ROYGBIV)

Richard Of York Gave Battle In Vain

Or just make up your own...

3.10 The Electromagnetic Spectrum

3.10 Understand that light is part of a continuous electromagnetic spectrum which includes radio, microwave, infrared, visible, ultraviolet, x-ray and gamma ray radiations and that all these waves travel at the same speed in free space.


The speed that the electromagnetic waves travel at in a vacuum (free space) is 299,792,458 m/s which is often rounded to 3.00 x 10⁸ m/s

3.9 Diffraction through gaps

Understand that waves can be diffracted through gaps, and that the extent of diffraction depends on the wavelength and the physical dimension of the gap

When a wave is sent through a gap it is diffracted on both sides as shown below:

When the wavelength is equal to the width of the slit, the most diffraction will occur:

3.8 Diffraction

Understand that waves can be diffracted when they pass an edge.


What is Diffraction?
Diffraction refers to various phenomena which occur when a wave encounters an obstacle. 
It is described as the apparent bending of waves around small obstacles and the spreading out of waves past small openings. (en.wikipedia.org/wiki/Diffraction)
Basically: Waves spreading into the shadow when they pass the edge

3.7 Using the previous relationships

Use the below relationships in different contexts, including sound waves and electromagnetic waves

Examples:

1. A certain sound wave has a frequency of 170 hertz (cycles per second) and a wavelength of 2 metres.

What is the speed of sound?

2.  The time period of a waves, T, is the time taken to produce one complete wave.

If the frequency of a wave is 2Hz, what is its time period?

Practice makes Perfect.

3.6 Frequency

Understand, and use the relationship between frequency and time period:

f = frequency (Hz) or (cycles/s)

T = Period (the time for one cycle) (s)

3.5 Wave speed

Understand the relationship between the speed, frequency and wavelength of a wave:

Wave speed = frequency x wavelength

or 

v = f x λ


This video explains the concept to a  greater extent

Thanks to brightstorm.com/science for the video