# Electromagnetic Waves

Wave: It is a temporary disturbance that transfers energy from one place to another. It divides into two:

1. Mechanical Wave

Longitudinal wave: it is a particle that vibrates in the direction of propagation of a wave.

Transverse wave: It is a particle that vibrates perpendicular to the direction of the wave.

2. Electromagnetic Wave

Red is the electric field; and is called wavelength; blue is a magnetic field.

• Matter, such as solid, liquid, gas, or plasma that mechanical waves are traveling through is called Medium.

ELECTROMAGNETIC WAVE

They do not require a medium to propagate. It can also travel not only through the air and solid materials but also through a vacuum space. They travel as vibrations in electrical and magnetic fields.

Notes to remember:

• Electricity and magnetism can be static, but changing the magnetic field will induce an electric field and vice versa.

• The electric field and magnetic field of an electromagnetic wave are perpendiculars (at right angles) to each other.

• It travels with a constant velocity of c= 3.0x 10^8 m/s in a vacuum space.

CHARACTERISTICS OF WAVES:

1. Amplitude (A)

The height of a wave is usually measured in meters (m). The greater amplitude of a wave, the more energy it’s carrying.

2. Wavelength

The distance between 2 consecutive crests or troughs, and usually measured in meters(m)

3. Frequency

The number of waves passing a point in a certain time. Gives a unit of Hertz (Hz).

4. Speed of light (c)

All electromagnetic waves travel at the same speed which is about c=3.0 x 10^8 m/s through a vacuum space.

A type of energy released by atoms that travel in the form of Electromagnetic waves. Including Gamma rays and X-rays. This is more dangerous to humans than non-ionizing radiation.

the part of the electromagnetic spectrum where there is insufficient energy to cause ionization.

• When an electric field changes, so do the magnetic field. Why? because the magnetic field causes the electric field to change. This will result in an equal electromagnetic wave.

## ELECTROMAGNETIC SPECTRUM

it is named for the range of electromagnetic waves when placed in order of increasing frequency.

$7 ELECTROMAGNETIC SPECTRUM:$

have the longest wavelengths but the shortest and lowest frequency.

2. MICROWAVES

have a shorter wavelength and have a higher frequency of radio waves.

3. INFRARED RAYS (below red)

shorter wavelength and higher frequency than a microwave.

4. VISIBLE LIGHT

shorter wavelength and higher frequency than infrared.

5. ULTRAVIOLET RAYS

it uses to kill bacteria.

6. X-RAYS

Can penetrate most matter.

7. GAMMA RAYS

carries the greatest amount of energy and it penetrates the most.

• Longest wavelength = Red light

• Shortest wavelength = Purple light