Suppose a ray of light traveling in a material with an index of refraction na reaches an interface with a material having an index of refraction nb. Which of the following statements must be true for total internal reflection to occur? a. The angle of incidence must be less than the critical angle.
b. The angle of incidence must be equal to the critical angle.
c. The angle of incidence must be greater than the critical angle.

The two required components for a generator

Apositive charge moves in the direction of an electric field. which of the following statements are true? check all that apply. check all that apply. 1.the potential energy associated with the charge decreases. 2. the electric field does positive work on the charge. 3. the electric field does negative work on the charge. 4. the potential energy associated with the charge increases. 5. the electric field does not do any work on the charge. 6. the amount of work done on the charge cannot be determined without additional information.

Lightning is an example of what phenomenon? a release of a large amount of energyan absorption of a large amount of energya natural electric circuita natural electric current