# Chapter 4 The Electromagnetic Spectrum Part 1. Demonstration Gas spectral tubes: NeonArgon.

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Chapter 4 The Electromagnetic Spectrum Part 1

Demonstration Gas spectral tubes: NeonArgon

Visible Light Part of the Electromagnetic Spectrum

All types of electromagnetic energy move in waves. Light and sound move by waves. Light moves at 3 x 10 8 m/s Sound moves at 340 m/s 1 mile = 1609 m

All types of electromagnetic energy move in waves. Light moves at 3 x 10 8 m/s Sound moves at 340 m/s Is sound a form of electromagnetic radiation?

Electromagnetic Waves Properties of waves include speed, frequency and wavelength All electromagnetic waves including light travel at a speed of 3 x 10 8 m/s.

) Wavelength ( ) Measured in units of length: m, nm, A º

) Frequency ( ) Measured in cycles/second = hertz (Hz)

Visible Light

For all waves = cFor all waves = c c = the speed of light = 3.00 x 10 8 m/sc = the speed of light = 3.00 x 10 8 m/s Electromagnetic Radiation

A photon of red light has a wavelength of 665 nm. What is the frequency of this light?

665 nm = 665 x 10 -9 m

A photon of red light has a wavelength of 665 nm. What is the frequency of this light? 665 nm = 665 x 10 -9 m c =

A photon of red light has a wavelength of 665 nm. What is the frequency of this light? 665 nm = 665 x 10 -9 m c = = c ÷ = 3.00 x 10 8 m/s ÷ 665 x 10 -9 m

A photon of red light has a wavelength of 665 nm. What is the frequency of this light? 665 nm = 665 x 10 -9 m c = = c ÷ = 3.00 x 10 8 m/s ÷ 665 x 10 -9 m = 4.511278 x 10 14 /s or Hz

A photon of red light has a wavelength of 665 nm. What is the frequency of this light? 665 nm = 665 x 10 -9 m c = = c ÷ = 3.00 x 10 8 m/s ÷ 665 x 10 -9 m = 4.511278 x 10 14 /s or Hz = 4.51 x 10 14 /s or Hz

An x-ray has a frequency of 7.25 x 10 20 Hz. What is the wavelength?

7.25 x 10 20 Hz = 7.25 x 10 20 /s

An x-ray has a frequency of 7.25 x 10 20 Hz. What is the wavelength? 7.25 x 10 20 Hz = 7.25 x 10 20 /s c =

An x-ray has a frequency of 7.25 x 10 20 Hz. What is the wavelength? 7.25 x 10 20 Hz = 7.25 x 10 20 /s c = = c ÷ = 3.00 x 10 8 m/s ÷ 7.25 x 10 20 /s

An x-ray has a frequency of 7.25 x 10 20 Hz. What is the wavelength? 7.25 x 10 20 Hz = 7.25 x 10 20 /s c = = c ÷ = 3.00 x 10 8 m/s ÷ 7.25 x 10 20 /s = 4.137931 x 10 -13 m

An x-ray has a frequency of 7.25 x 10 20 Hz. What is the wavelength? 7.25 x 10 20 Hz = 7.25 x 10 20 /s c = = c ÷ = 3.00 x 10 8 m/s ÷ 7.25 x 10 20 /s = 4.137931 x 10 -13 m = 4.14 x 10 -13 m

Energy of Waves

For all waves: E = hFor all waves: E = h h = 6.63 x 10 -34 J s or J/Hz Energy of Electromagnetic Radiation

A photon of red light has a wavelength of 665 nm. What is the energy of this light?

665 nm = 665 x 10 -9 m c = = c ÷ = 3.00 x 10 8 m/s ÷ 665 x 10 -9 m = 4.511278 x 10 14 /s or Hz = 4.51 x 10 14 /s or Hz

A photon of red light has a wavelength of 665 nm. What is the energy of this light? 665 nm = 665 x 10 -9 m c = = c ÷ = 3.00 x 10 8 m/s ÷ 665 x 10 -9 m = 4.511278 x 10 14 /s or Hz = 4.51 x 10 14 /s or Hz E = h = (6.63 x 10 -34 J s)(4.51 x 10 14 /s)

A photon of red light has a wavelength of 665 nm. What is the energy of this light? 665 nm = 665 x 10 -9 m c = = c ÷ = 3.00 x 10 8 m/s ÷ 665 x 10 -9 m = 4.511278 x 10 14 /s or Hz = 4.51 x 10 14 /s or Hz E = h = (6.63 x 10 -34 J s)(4.51 x 10 14 /s) E = 2.99013 x 10 -19 J

A photon of red light has a wavelength of 665 nm. What is the energy of this light? 665 nm = 665 x 10 -9 m c = = c ÷ = 3.00 x 10 8 m/s ÷ 665 x 10 -9 m = 4.511278 x 10 14 /s or Hz = 4.51 x 10 14 /s or Hz E = h = (6.63 x 10 -34 J s)(4.51 x 10 14 /s) E = 2.99013 x 10 -19 J = 2.99 x 10 -19 J

An x-ray has a frequency of 7.25 x 10 20 Hz. What is its energy?

An x-ray has a frequency of 7.25 x 10 20 Hz. What is it’s energy? E = h = (6.63 x 10 -34 J/Hz)(7.25 x 10 20 Hz)

An x-ray has a frequency of 7.25 x 10 20 Hz. What is it’s energy? E = h = (6.63 x 10 -34 J/Hz)(7.25 x 10 20 Hz) E = 4.80675 x 10 -13 J

An x-ray has a frequency of 7.25 x 10 20 Hz. What is it’s energy? E = h = (6.63 x 10 -34 J/Hz)(7.25 x 10 20 Hz) E = 4.80675 x 10 -13 J E = 4.81 x 10 -13 J

wavelength, frequency and energy = 665 x 10 -9 m = 4.51 x 10 14 Hz E = 2.99 x 10 -19 J = 4.14 x 10 -13 m = 7.25 x 10 20 Hz E = 4.81 x 10 -13 J Red Light X-ray

Wavelength, frequency and energy Wavelength and frequency have an indirect relationship. Energy and frequency have a direct relationship. Electromagnetic radiation with a shorter wavelength will have a higher frequency and higher energy. Electromagnetic radiation with a longer wavelength will have a lower frequency and lower energy.

Homework Chapter 4: Worksheet 2 (due in two days)

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