# Electromagnetic waves

### Wave

A wave is a disturbance that transfer energy from one place to another. It does not transfer matter during the energy transfer.

### Electromagnetic wave

Electromagnetic waves are created by accelerating charges.EM waves are composed of oscillating magnetic and electric fields.

Electromagnetic waves are formed when an electric field couples with  magnetic field. Both fields are perpendicular to each other and to the direction of the wave propagation. Electromagnetic waves propagate at the speed of light.

Light wave, microwaves you use to heat up food and the radio waves that are broadcast from radio stations are some examples of electromagnetic waves.

### Electromagnetic wave production

Electromagnetic waves are produced by moving charges. Back and forth motion will produce oscillating electric and magnetic fields.

### Properties of Electromagnetic wave

• EM waves are made up of Electric and Magnetic fields that are at right angles to each other and at right angles to the direction of propagation. Transverse in nature.
• EM wave travels in a straight line.
• EM waves travels at approximately speed of light 2.99×10^8 m/s.
• They transfer energy from one place to another.
• When enters from one medium to another, speed and wavelength change.
• Speed of light in air = 3×10^8 & in water = 2.25×10^8.
• They obey the law of reflection and refraction.

### Electromagnetic Spectrum

EM Spectrum is the arrangement of EM waves in order of frequency and wavelength. EM waves are invisible except small portion of light.

Electromagnetic spectrum is divided into seven parts, in order of decreasing wavelength and increasing energy and frequency.