Page 226 - text book form physics kssm 2020

5.7 Electromagnetic Wavesaves
Electromagnetic W

Characteristics of Electromagnetic Waves
Figure 5.68 shows briefl y the history of early scientifi c discoveries which brought about the
present knowledge regarding electromagnetic waves.

1801 1862 1887 Early 20th century
Th omas Young James Maxwell put Heinrich Hertz Electromagnetic
showed that light forth the theory generated a waves are made up of:
is a wave through that light is an diff erent kind of 1. Gamma ray
experiments on electromagnetic wave. electromagnetic 2. X-ray
interference of light. wave, that is 3. Ultraviolet ray
radio wave. 4. Visible light
5. Infrared ray
6. Microwave
7. Radio wave

Figure 5.68 History of electromagnetic waves
Magnetic field, B
Direction of
Electromagnetic waves are made up of an Electric field, E propagation
electric fi eld and a magnetic fi eld that oscillate
perpendicularly to one another, as shown in Figure
5.69. What are the characteristics of electromagnetic
waves?

Figure 5.69 Electromagnetic waves

Activity 5.23 ICS

Aim: To search for information related to the characteristics of electromagnetic waves
Instructions:
1. Work in groups.
2. Search for information related to the characteristics of electromagnetic waves for the
following aspects:
(a) types of waves
(b) requirement of medium for propagation
(c) speed in vacuum
(d) speed in medium
(e) wave phenomena
3. Present your fi ndings using a suitable mind map and put up on a notice board for
information sharing.

220 5.7.1
220
5.7.1