Can someone please help me with this.. Q. A sphere of mass 10.0 was charged negatively. It was held, floating 2.5cm above an object carrying a charge of -1.4 ×10^-7C. what charge would be carried by the sphere.

Which statement is true if the refractive index of medium a is greater than that of medium b? a. total internal reflection is possible when light travels from air to medium b to medium a. b. total internal reflection is possible when light travels from medium a to medium b. c. total internal reflection is possible when light travels from medium b to medium a. d. total internal reflection is possible when light travels from air to medium a. e. total internal reflection is possible when light travels from air to medium b.