The refractive index of water is 4/3. How much time will it take to light to travel through a water column of length 500 m?

2.22 x \( {10 }^{ -6} \) 2.22 x \( {10 }^{ -5} \) 3.12 x \( {10 }^{ -6} \) 3.12 x \( {10 }^{ -5} \)

2.22 x \( {10 }^{ -6} \)

Use :  μ = c/v v = c/μ  t=500 m/v