Plutonium-239 is one of the isotopes used for fuel in nuclear power plants. It has a half life of 24,000 years. If 100 grams of it were left in a hole, how long until there is only 12.5 grams remaining?

How hot is the suns corona? (integrated science)

In france, grapes are 1.95 euros per kilogram. what is the cost of grapes, in dollars per pound, if the exchange rate is 1.14 dollars/euro? (2.6)

Pegmatites are igneous rocks in which the individual minerals are very large. typically, the minerals are all light-colored quartz, feldspar and muscovite. if you were given a black and white photograph of a pegmatite in a quarry (where the rock has been blasted and broken), what physical properties could you use to identify those three minerals in this hypothetical photo? describe each mineral and the specific diagnostic properties. be specific.