is the sum of angle of reflection and incidence always 90 degrees??????

Hi,

No, the law of reflection states that when a ray of light reflects off a surface, the angle of incidence is equal to the angle of reflection.

Therefore, if angle of incidence is 30⁰ then according to the law of reflection angle of reflection will also be 30⁰. Now, summing both the angles will not give us 90⁰.

Hope this helps,

Good luck.