• Brainly User

This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
By passing the beam of light in that certain liquid and then calute its 
1angle of incidence
2angle of refraction
as these are very small angle so we can take sine of that angles
now according to snell's law
sin i/sin  r= refractive index