posted by sweetie .
1)if angle of incidence is 56 and it is decreased by 15 dagree then draw the path of a ray by drawing a diagram by using exact value of angle of incidence and angle of refraction.as refractive index of glass is 1.5.
2)name the phenomenon of light which u observe above.
In your question, it is not clear which angle is being decreased by 15 degrees. If they want you to calculate the angle of refraction for 56-15 = 41 degree incidence, then use Snell's law for the new angle of refraction.
We cannot draw figures for you. You will have to do that yourself.