If the speed of light in a sphere is 2 × 108 m/s, its index of refraction is

Refractive index, n = v1/v2

Where,
v1 = Speed of light in vacuum = 3*10^8 m/s
v2 = Speed of light in a medium (sphere) = 2*10^8 m/s

Therefore,
n= (3*10*8)/(2*10^8) = 1.5

Jet streams are relatively narrow bands of strong wind in the upper levels of the atmosphere. the winds blow from west to east in jet streams but the flow often shifts to the north and south. jet streams follow the boundaries between hot and cold air. the earth's rotation is responsible for the jet stream as well.