<h2>Answer:</h2>
The refractive index is 1.66
<h2>Explanation:</h2>
The speed of light in a transparent medium is 0.6 times that of its speed in vacuum
.
Refractive index of medium = speed of light in vacuum / speed of light in medium
So
RI = 1/0.6 = 5/3 or 1.66
Answer:
They can be seen from a distance of 4.372 kilometers.
Explanation:
Using the Reyligh creterion for diffraction through a circular aperture we have
where symbol's have their usual meaning
thus applying values we get


The free fall of the phone is an uniformly accelerated motion toward the ground, with constant acceleration equal to

So, assuming the downward direction as positive direction of the motion, since the phone starts from rest the distance covered by the phone after a time t is given by

And if we substitute t=2.7 s, we find the distance covered: