Everything Science Grade 10

CHAPTER 11. ELECTROMAGNETIC RADIATION 11.5

Chapter 11 | Summary

See the summary presentation ( Presentation: VPfhw at http://www.everythingscience.co.za)

• Electromagnetic radiation has both a wave and a particle nature.


• Electromagnetic waves travel at a speed of approximately 3 × 108 m·s−^1 in a vacuum.


• The Electromagnetic spectrum consists of the following types of radiation: radio
  waves, microwaves, infrared, visible, ultraviolet, X-rays, gamma-rays.


• Gamma-rays have the most energy and are the most penetrating, while radio waves
  have the lowest energy and are the least penetrating.

Physical Quantities

Quantity Unit name Unit symbol

Energy (E) joule J

Wavelength (λ) metre m

Period (T) second s

Frequency (f) hertz Hz (s−^1 )

Speed of light (c) metre per second m·s−^1

Table 11.3: Units used inelectromagnetic radiation

Chapter 11 End of chapter exercises

1. What is the energy of a photon of EM radiation with a frequency of 3 ×

108 Hz?

2. What is the energy of a photon of light with a wavelength of 660 nm?

3. What is the energy of a photon of light with a frequency of 13 THz?

4. What is the wavelength of a photon of light with a frequency of 101.3 kHz?

5. What is the energy of a photon of light with a wavelength of 532 nm and

one with a frequency of 13 GHz and which has the longer wavelength?

Physics: Waves, Sound and Light 201