Which behavior is not true for incident rays striking a concave mirror? a. incident rays parallel to the principal axis are reflected to the focus
b. incident rays passing through the focus are reflected parallel to the principal axis
c. incident rays passing through the center are reflected back to the center.
d. incident rays from an object at infinity and parallel to the principal axis are reflected to the center.

Balloon a has charge q, and identical mass balloon b has charge 10q. you hang them from threads near each other. choose all of the statements with which you agree. check all that apply. a. a and b exert the same magnitude forces on each other. b. the force that a exerts on b is 10 times the force that b exerts on a. c. the angle between the thread supporting a and the vertical is < the angle between the thread supporting b and the vertical. d. the force that a exerts on b is 1/10 the force that b exerts on a.