Question

Write rules to find the direction of deflection of a ray of light as it travels from one medium to another.

Answer 1

make a perpendicular to the Ray where it has started bending
extend the Ray further to the perpendicular
now if the medium is rarer and Ray is traveling from denser medium then bend the away from the extend incident Ray otherwise bend the toward the extended incident ray.

Answer 2

whenever light travels from rarer medium to denser medium it bend towards normal (the line perpendicular to the refracting surface and it divides the incident angle and reflected angle equally) and it goes away from normal if it travels from denser to rarer medium .