15 if an object gains_ it has an electrical charge
16 the instrument used to measure electrical charge
18 a decreases the amount of electricity coming into our homes
24 electrical_ is the rate at which electrical energy is converted

15. electrons

16. electrometer

18. Transformers

24. Power

Explanation:

The fundamental charges in nature are electrons and protons.The electrons have negative charges and protons have positive charges.The proton with similar other protons forms the nucleus of an atom. Mostly it doesn't exist freely in nature. it is not easy to knock out a proton from an atom.Whereas, the electrons were present in the outer sphere if the nucleus of an atom.Compared to a proton, It is easy to remove an electron from an atom.So, if an object gains some electrons, it acquires some charges.The amount of such charges can be measured using a device called electrometer.The flow of electrons is associated with energy. This energy is called electrical energy and it can be converted into other forms of energy.The rate at which electrical energy is converted to some other forms of energy is called electrical power.