There are fiber optic telephone cables connecting North America and Europe, lying on the bottom of the Atlantic ocean. The wire is 4,500 km long how long and has an index of refraction of 1.5. How long will it take for the signal to cross the ocean? Give your answer in milliseconds.

The time taken is

Explanation:

From the question we are told that

    The length of the wire is

      The  refractive index is  

The velocity of the signal is mathematically represented as

Where c is the speed of light with value

 substituting values  

The time taken is mathematically evaluated as

substituting values  

real, smaller and upside-down.   so the answer should be b.