 # what is the angle of deviation of a plane mirror? 11 years ago

Dear Nivedhitha,

A ray of light that is incident on to the surface of a plane-mirror is reflected with the angle of incidence equal to the angle of reflection. Suppose that the ray had continued, through the mirror, in a straight line it would make an angle θ with the surface of the mirror. The total angle between the straight-line path and the reflected ray is twice the angle of incidence. This is called the deviation of the light and measures the angle at which the light has strayed from its initial straight-line path.

A ray of light that is incident on to the surface of a plane-mirror is reflected with the angle of incidence equal to the angle of reflection. Suppose that the ray had continued, through the mirror, in a straight line it would make an angle θ with the surface of the mirror. The total angle between the straight-line path and the reflected ray is twice the angle of incidence. This is called the deviation of the light and measures the angle at which the light has strayed from its initial straight-line path.

"The deviation of a mirror is equal to twice the angle of incidence"

i will give the figure for the above one.. in the above figure The deviation of light is twice the angle of incidence.

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6 years ago
Yes, angle of incidence should be calculated wth the normal, because the angle between the incident ray and te normal is called angle of incidence.
5 years ago
U just double the angle of incidence or reflection which is given and hence you will get the angle of deviation. And if you want to find the angle of incidence for a prism then you can subtract two times of angle of incidence from 180 degree and you will get the angle of deviation
3 years ago
Deviation caused by single reflection =180-2i.        (i=angle of incidence ) this is the formula for the given question NIVEDHITHA