7. a. What is the cause of refraction?
b. Define the term principal focus of concave mirror.
Answers
Explanation:
A. The cause of refraction of light is that light travels with different speeds in different media. This Change in the speed of light when it moves from one medium to another causes it to bend.
B. A concave mirror, or converging mirror, has a reflecting surface that is recessed inward (away from the incident light). Concave mirrors reflect light inward to one focal point. They are used to focus light.
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Answer:
1)the refraction whenever it travels at an angle into a substance with a different refractive index (optical density).this change of direction is caused by a change in speed when light travels from air into water it slows down causing it to change direction slightly. this change of direction is called refraction
2)light tays that are parallel to the principals axis of a concave mirror converge at a specific points on its principal axis after reflecting from the mirror.this point is known as the principal focus of the concave mirror