Physics Lesson Note Grade 10
Unit – Six
Electromagnetic waves and Geometrical optics
- Electromagnetic waves are waves which are transverse waves and that do not requires
material medium to propagate - Electromagnetic waves are waves produced when a magnetic field and electric fields are
at right angle to each other
Electromagnetic spectrum: is the entire frequency range of electromagnetic waves
The following are some of the electromagnetic spectrum with their wave length
R-rays X-rays U.V Visible Infrared Micro Radio
light rays waves waves
Wave
length 10-
12m
10-10m 10-8m 10-7m 10-6m 1o-2m 1m
N.B all electromagnetic waves travel in vacuum at the same speed of 3x108m/s some
applications and electromagnetic radiation
Some applications and electromagnetic radiation - X – rays: Are used to take a picture of inside our body
➢ Used for to kill cancer cells - Ultraviolet rays (u.v.r): used for in sterilization and acceleration of chemical reaction
➢ They are also sources of vitamin D and sometimes too much of them will
cause cancer and blindness - Visible light: used in vision i.e. to see objects clearly
- Infrared wares (rays): used for cameras of infrareds
- used in rescues operations
Micro waves – used for cooking foods - used for communication
- used for supermarket to detect customers
