The material should be considered as the glycerol (n=1.47).
Since
a beam of monochromatic light (f=5.09 × 10^14 Hz) has a speed of 2.04× 10^8 meters per second.
Now the material should be
= 3*10^8 / 2.04× 10^8
= 1.47
Hence, The material should be considered as the glycerol (n=1.47).
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