Definition of 'optimum'. Word Frequency. optimum (ÉptÉªmÉm ) or optimal. adjective. The optimum or optimal level or state of something is the best level or state that it could achieve. [formal] Aim to do some physical activity three times a week for optimum health. ...regions in which optimal conditions for farming can be created.
Quick Answer. Pennies produced by the U.S. Mint since 1982 are an alloy of 2.5 percent copper and 97.5 percent zinc. The penny weighs 2.5 grams, so each penny contains 0.0625 grams of copper.
A penny is not what you think. Indeed, from 1783 to 1837, a cent was pure copper. But newer pennies are made mostly of zinc. Here's the history, according to the U.S. Mint: 1  From 1837 to 1857, the cent was made of bronze (95 percent copper, and five percent tin and zinc). 2  From 1857, the cent was 88 percent copper and 12 percent nickel, giving the coin a whitish appearance.