That could be a power cell (battery), or more correctly, a capacitor.
transformer
A battery is a device that stores and produces electrical energy by converting chemical energy into electrical energy through electrochemical reactions.
A flywheel is a device that stores mechanical energy by spinning continuously and maintaining rotational motion even after the input energy has stopped.
Electrial energy
we used pawan chakki to transformed its electrial energy
heat energy is converted into electrial enegry when passed from magnetic energy
True. Light is a form of electromagnetic energy.
A battery is a device that stores energy in the form of chemical energy that can later be converted into electrical energy.
A battery is a device that converts mechanical energy into chemical energy. It stores this energy in the form of chemical reactions that can later be converted back into electrical energy to power a device.
It isn't "the best"; it is useful for some specific purposes.
Many call batteries this but there are others such as a chemical called ATP.
An iPad uses electrical energy from its battery. When the battery is charged, it stores this electrical energy to power the device's functions.