a flashlight is a kind of battery-operated device & battery is the source of electrical energy for battery-operated device ->  battery is the source of electrical energy for a flashlight  a flashlight is a kind of electrical device & electrical devices convert from electrical energy  into other forms of energy ->  a flashlight converts electrical energy into other forms of energy  a flashlight converts electrical energy into other forms of energy & a kind of is similar to a form of & a flashlight emits light & light is a kind of energy ->  a flashlight converts electrical energy into light energy  battery is the source of electrical energy for a flashlight & a flashlight converts electrical energy into light energy ->  a flashlight converts electrical energy from the battery into light energy  a flashlight converts electrical energy from the battery into light energy & batteries convert chemical energy to electrical energy -> when a flashlight is used, the energy is changed from chemical energy into electrical energy and then into light energy