How does a concave lens differ from a convex lens? a) a convex lens is another way to describe a plane mirror; a concave lens is curved. b) a concave lens us curved inward on both sides; a convex lens is curved on only one side. c) a convex lens has a thick center and thin edges; a concave lens has a thin center and thicker edges. d) a convex lens has a thin center and thick edges; a concave lens has a thick center and thiner edges.

C) A convex lens has a thick center and thin edges; a concave lens has a thin center and thicker edges.

c. A convex lens has a thick center and thin edges; a concave lens has a thin center and thicker edges.

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.