B What mass of the original isotope will remain after 120 minutes? Ra-226 has a half-life of 1600 years and decays by alpha emission.
A.
What period of time will be required for 20. grams of this radioisotope to decay to 5.0 grams?

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.