Question

if the angle between mirror and incident ray is 40 Degrees then find the angle of reflection​

Answer 1

angle of reflection is the same 40 degrees.........

Answer 2

we know that angle of incidence is equal to angle of relection.  

the angle between incident ray and mirror is 40

imagining a normal to it,(90 degrees because it is perpendicular)

so angle of incidence is 90-40=50( angle between normal and incidence.)

so angle of reflection is also 50