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.
If you weigh a zinc penny on a scale that can only register full 1 gram increments, the penny will usually display 3 grams, since the scale rounds the 2.5 gram zinc penny upwards to 3. The wrong type of scale can be misleading when you are trying to sort copper and zinc pennies.