Flash Light - By Shashank Soni description

A flashlight is a portable hand-held electric light.
The source of the light is usually an incandescent
light bulb (lamp) or light-emitting diode (LED).
A typical flashlight consists of the light source mounted
in a reflector, a transparent cover (sometimes combined
with a lens) to protect the light source and reflector,
a battery, and a switch. These are supported and protected by a case.

The invention of the dry cell and miniature incandescent
electric lamps made the first battery-powered flashlights
possible around 1899. Today, flashlights use mostly
incandescent lamps or light-emitting diodes and run on disposable
or rechargeable batteries. Some are powered by the user turning
a crank or shaking the lamp, and some have solar panels
to recharge a battery.

In addition to the general-purpose hand-held flashlight, many
forms have been adapted for special uses. Head or helmet-mounted
flashlights designed for miners and campers leave the hands
free. Some flashlights can be used underwater or in flammable
atmospheres. Flashlights are used as a light source when in
a place with no power.