When the surface of a mirror curves outwards, like the back of a soon , it's called a

Why there is no inductive reactance in dc circuits

Which is not true about oxygen-17 and oxygen-18?

30 points - when can a theory be modified if a new type of technology allows for new observations that raise new questions? a. immediately, while the questions about the theory are being asked b. after new hypotheses related to the theory are tested in experiments c. only after the new observations disprove all parts of the theory d. while scientists begin to think about how the theory could improve