An electric bulb is one of the revolutionary inventions ever made in the history of mankind. The working of an electric bulb is quite simple. When electric current flows through the filament made up of tungsten, it heats up emitting visible light.
The above image shows a commonly used electric bulb. The entire assembly is housed in an envelope of glass. The shape of the glass is responsible for giving directionality to the light.
The above image shows a closer look inside the outermost glass covering. The different parts of the bulb are visible in this image.