Asample contains 24 g of a radioactive isotope. how much radioactive isotope remains in the sample after 2 half-lives?

a. 3 g
b. 6 g
c. 12 g
d. 1.5 g

Which sentences describe disadvantages of burning fossil fuels instead of using hydrogen fuel cells? burning fossil fuels contributes to climate change. burning fossil fuels takes place inside expensive fuel cells. fossil fuels aren't widely available, but pure hydrogen is. fossil fuels are nonrenewable.

Two polarizers are oriented at 70∘∘ to one another. unpolarized light falls on them. what fraction of the light intensity is transmitted?

Which describes increasing the efficiency of energy resource