Give a formula for pi using D. pi =

Which of the following correctly describes the early view of catastrophism?

How does the image distance (di) of a convex lens compare with the image distance of a concave lens? a. the image distance of the convex lens is positive, and that of the concave lens is negative. b. both are negative for a virtual image. c. both are positive for a virtual image d. the image distance of the convex lens is negative, and that of the concave lens is positive.

Select the word from the list that best fits the definition classification of most stars on the h-r diagram