PLEASE HELP!! Which statement is correct?

The speed of the light ray is the same in air and in Medium A.
The speed of the light ray is the same in air and in Medium B.
Medium A is denser than Medium B because light bends more in Medium A.
Medium B is denser than Medium A because light bends more in Medium B.

The material that keeps its new shape after it is stretched is called?

How many atoms of nitrogen are in the chemical formula ni(w on

Four point charges each having charge q are located at the corners of a square having sides of length a. find symbolic expressions for the following. (a) the total electric potential at the center of the square due to the four charges (use any variable or symbol stated above along with the following as necessary: ke.) vtotal= (b) the work required to bring a fifth charge p from infinity to the center of the square (use any variable or symbol stated above along with the following as necessary: w=