please answer question 1-3

Lab 8: Pre-Lab Questions (15) 1. A lens has two focal points or foci, as shown in the drawings below. (a) A convex-convex lens is a converging lens. Prays that enter the lens from the left side will converge at and pass through the focal point on the right or far side. The focal point on the left or near side is not used. Sketch three P-rays passing through the converging lens provided. Note: instead of refracting the ray at each interface, assume the ray refracts only once, at the dashed central bisector of the lens. (3 pts.) (b) A concave concave lens is a diverging lens. P-rays entering from the left will diverge away from the focal point on the left. The right-side focal point is not used. Sketch three P-rays passing through the diverging lens provided. (3 pts.) 2. Light refracts from air (n = 1.0) into an unknown substance. The angles of incidence and refraction are 61 = 42 and 02 = 180, respectively. What is the index of refraction of the unknown substance? (3 pts.) 3. Use Equations 1 and 2 from the lab to solve the following: (a) Find the critical angle, 0, for light refracting from glass (ng = 1.58) into water (nw = 1.33). (3 pts. (b) Find the critical angle, de, for light refracting from glass (ng = 1.58) into air (n. = 1.00). (3 pts.) 96