The half life of uranium-235 is 4.5 billion years. If 0.5 half-lives have elapsed, how many years have gone by? a.9 billion
b.2.25 billion
c.4.50 billion
d.4.0 billion

Which term best describes the phrase “something that happens”?

What is created when solids,liquids,an gases mix with one another

Unpolarized light of intensity i_0=750w/m^2 is incident upon two polarizers. after passing through both polarizers the intensity is i_2=280w/m^2. (a) what is the intensity of the light after it passes through the first polarizer in w/m^2? (b) write an equation for the angle between the polarizers in terms of the initial (i_0) and final (i_2) intensities. (c) find the angle between the polarizers in degrees.