1. Decrease in intensity of a signal, beam, or wave as a result of absorption of energy and of scattering out of the path of a detector, but not including the reduction due to geometric spreading, i.e., the inverse square of distance effect.
For the purists, there are about 145 copper cents / pennies in a pound. On the other hand, post 1982 zinc cents which have a copper plating over a much softer, much lighter zinc planchet. So there are about 180 zinc cents / pennies per pound. Those numbers of pennies per pound are of course for new, uncirculated, zinc or copper cents. When minted, new copper cents weigh about 3.11 grams each and new zinc cents about 2.5 grams each and that is our basis for the number of pennies in a pound. However, once they are put in circulation, they start to ware thinner and thinner.
Much less expensive zinc makes up 97.5% of the mass of a penny, the rest is a copper coating. Nickels actually have much more copper in them -- 75% copper and 25% nickel. It's the same mix they have always had except for the World War II years, when silver and manganese replaced the nickel and some of the copper.