What is light emitting diode (LED)? Explain its working principle and state factor on which the colour of light emitted by it depends.

Light Emitting Diodes, commonly known as LEDs, are semiconductor devices that emit light when an electric current passes through them. They are widely used in various applications, from indicator lights to large display screens.

How LEDs Work

The operation of an LED is based on a principle called electroluminescence. When electricity flows through the diode, electrons recombine with holes in the semiconductor material, releasing energy in the form of photons, which is visible light.

Key Components

• Semiconductor Material: Typically made from gallium arsenide or gallium phosphide.
• Electrodes: Allow current to enter and exit the diode.

Factors Influencing Light Color

The color of light emitted by an LED depends primarily on the energy band gap of the semiconductor material used. This band gap determines the wavelength of the light produced. Here are some factors to consider:

• Material Composition: Different materials emit different colors.
• Current Flow: The amount of current can slightly affect the color and intensity.

In summary, LEDs are efficient light sources that operate through the electroluminescence of semiconductor materials, with their color determined by the specific materials and their properties.