Answer:
Explanation:
velocity of light in a medium of refractive index V = V₀ / μ
V₀  is velocity of light in air and μ is refractive index of light.
time to travel in tube with air = Â length of tube / velocity of light
8.72 ns = L / Vâ‚€ Â L is length of tube .
time to travel in tube with jelly = Â length of tube / velocity of light
8.72+ 1.82 Â = L / V Â L is length of tube .
10.54 ns = L / V
dividing the equations
10.54 / 8.72 = Vâ‚€ Â / V
10.54 / 8.72 =  μ
1.21 =  μ
refractive index of jelly = 1.21 .