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.
Since even the newest pennies still use at least 2.5% copper (mostly as the outer plating over the mostly zinc inner core), and all years except 1943 used at least 95% copper in the making of pennies, 1943 is the only year that no copper was used in the making of U.S. pennies.