Which one of the following statements is true concerning the magnitude of the electric field at a point in space? It is a measure of the electric force on any charged object. It is a measure of the ratio of the charge on an object to its mass. It is a measure of the electric force per unit mass on a test charge. It is a measure of the electric force per unit charge on a test charge. It is a measure of the total charge on the object.

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.