A flashlight primarily uses electrical energy to function. When you turn on the flashlight, electrical energy stored in its batteries is converted into light energy through a process in which electricity flows through the filament or LED (light-emitting diode) bulb.
The batteries provide the necessary power, and depending on the type of flashlight, it might use different battery chemistries such as alkaline, lithium, or rechargeable nickel-metal hydride (NiMH) batteries. These batteries release energy that powers the flashlight, creating a bright beam of light.
In summary, a flashlight converts electrical energy into light energy, enabling it to illuminate dark areas effectively.