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Question 6 1 pts Light having a frequency in vacuum of 8 MHz enters a liquid of refractive index n = 1.7. What is the frequency of the light in the liquid? O 23 GHZ O 72 KHz O 16 GHz O 8 MHz Question 7 1 pts Light travels from a material with a refractive index of 1.57 into water, which has a refractive index of 1.33. What is the critical angle for this interface? O 60 350 O 720 580Question 8 1 pts A plastic plate having an index of refraction is 1.55 is immersed in a certain alcohol. The surface of the glass is inclined at an angle of 52 with the vertical. When a horizontal ray in the glass strikes the interface, you observe that it is at the critical angle. What is the index of refraction of the alcohol? 1.93 1.04 1.22 1.65 Question 4 1 pts A laser beam strikes the perfectly reflecting surface of a plane mirror. The beam has an angle of incidence of 170. What is the angle between the normal to the plane and the reflected ray? 120 O 310 O 170 O 250