Pop Quiz
On a piece of paper write your name and the answers to the
following questions. When you are finished place your answers in
the tray on my desk. You have 10 minutes
•What are the prefixes represented by the ‘King Henry Died by
drinking chocolate milk’ acronym.
7 points
•Convert the following into meters. Use scientific notation
475nm 4.75x10-7m
25cm
1500km
=2.5x10-1m
1.5x106m
3 points
Electromagnetic Spectrum
Wavelength
‘The distance between successive crests of a wave’
Frequency
‘the number of periodic oscillations, vibrations or waves
occurring per unit of time’
Relationships
frequency, (s-1)
velocity, (m/s)
c=λν
wavelength, (m)
Wave Particle Duality
Electromagnetic radiation fits the rules of behavior
for both waves and particles. This is known as waveparticle duality
The reason for this is that just thinking of light (or
any type of radiation) as a wave doesn’t explain certain
things.
Task: Use p84 of the black study guide to make notes
of wave- particle duality. You have 10 minutes
The energy of a photon (a particle of light or
electromagnetic radiation) can be calculated using the
following formula
Planck’s constant,
6.63x10-34 Js
E=hν
Energy, kJ/mol
Frequency, s-1
As you can see energy is directly related to frequency
Questions:
Which of the following has a longer wavelength?
•Red light or blue light?
•Microwaves or radio waves?
•Infrared radiation or red light?
•Gamma rays or uv radiation?
Which of the following has a greater frequency?
•Yellow light or green light?
•X-rays or gamma rays?
•UV radiation or violet light
•AM radio waves or FM radio waves
Which of the following has the lower energy?
(remember energy is directly related to frequency)
•Red light or blue light?
•Microwaves or radio waves?
•Gamma rays or uv radiation?
•UV radiation or violet light?
Springfields ‘Classic Rock’ radio station broadcasts at a frequency
of 102.1 MHz. What is the length of the radio wave in meters?
(1 MHz = 1x106 Hz)
c=λν
3x108
λ
=
3x108
= 102.1x106
=
2.94m
λ
x
102.1x106
A beam of light has a wavelength of 506 nanometres.
What is the frequency of the light? (1nm= 1x10-9m)
What colour is the light?
c=λν
3x108
ν
= 506x10-9
3x108
= 506x10-9
=
5.93 x1014Hz
x
ν
Blue light has a frequency of 6.98x1014 Hz. Calculate
the wavelength of blue light
c=λν
3x108
3x108
λ = 6.98x1014
=
4.30x10-7m
or
430nm
14
x
6.98x10
= λ
Now complete the worksheet. It should be handed in at the
end of the lesson
Homework: Answer q5&6 on p126 0f the textbook