If the angle of a light ray in air is 25∘ and it enters a substance with a refracted angle of 13∘, what is the index of refraction of the substance? A). 0.65

B). 0.53

C). 1.92

D). 1.88

Aballoon is rising vertically upwards at a velocity of 10m/s. when it is at a height of 45m from the ground, a parachute bails out from it. after 3s he opens his parachute and decelerates ata a constant rate 5m/s.when. (a) what was the height of the parachutist above the ground when he opened his parachute? (b)how far is the parachutist from the balloon at t=3s? (c)with what velocity does the parachutist hit the ground? (d)after how long does the parachutist hit the ground after his exist from the balloon?