When the line from the light source to the surface on which the shadow falls is perpendicular to that surface.
Answer: when you look into it with your hideous mug Answer: This may happen when the mirror falls on the floor.
it reflects all of the light that falls on it. To act as a mirror the surface needs be smooth.
Only a perfectly smooth surface can produce a clear reflection - i.e. a mirror. The less smooth (rougher) the surface the blurrier the image.
A highly polishes plane surface which reflects light regularly is called a plane mirror. Image is formed as the light returns to the first medium when it just falls on the other surface of the second medium.
It is the angle at which the incoming light beam strikes the mirror. 'Normal' means 'perpendicular', and the 'angle of incidence' is defined as the angle with respect to the normal. These two facts can serve as powerful clues.
if ray of light falls normally ,it is reflected back along the same path
Substitute "photon" for "ray" and it's one. One photon falling on a plane mirror will come back off of the reflective surface if that reflective surface does not absorb it. (In a perfect plane mirror, every photon that falls on the surface will be reflected.) A photon does not "create" a second photon in a reflection event.
what will happen if falls from a dam
it reflects !
reflection is when light its something like a mirror and refraction is light going through something solid that is not like a mirror when light falls on a surface and bounces back, it is reflection and when light is absorbed by the surface or passes through the surface but does not bounces back, it is refraction.
That ray of light is just a radius of the sphere. It's perpendicular to the sphere everywhere, so the angle of incidence is zero ... the ray of light arrives along the normal to the mirror at any point.