Units in physics are used to measure physical quantities such as energy, force, and electric and magnetic fields. The most commonly used units in physics are ATOMS (5 letters), ergs (4 letters), egs (3 letters), and teslas (6 letters). ATOMS are the smallest unit of matter and are used to measure the amount of a substance. Ergs are a unit of energy and are used to measure work or heat. Egs are a unit of electric field strength and are used to measure the force of an electric field. Teslas are a unit of magnetic field strength and are used to measure the force of a magnetic field.