A laser beam shown in the figure below enters a solid glass sphere and reaches the back of it. The sphere has an index of refraction of 2.4. Assume the sphere is surrounded by air. horizontal laser beam reference line along reference lines redins of sphere reference line along radius of sphere (a) (15) Find what the angle 0 must be in order for the refracted beam to reach the back of the sphere. The dashed lines are supposed to be reference lines. (b) (5) Does beam that strikes the back of the sphere undergo total internal reflection? Find the critical angle at the point where the beam hits the back of the sphere and use it to explain whether total internal reflection occurs at the back of the sphere or not