In a reflecting periscope , if a light ray is incident at 45^(@) angle at the first plane mirror, then the angle of deviation of light ray by the periscope is ______ .

In a reflecting periscope , if a light ray is incident at 45^(@) angle

1.	In a reflecting periscope , if a light ray is incident at 45^(@) angle at the first plane mirror, then the angle of deviation of light ray by the periscope is ______ .
Answer» `30^(@)` `90^(@)` `180^(@)` zero Solution :`i=45^(@)` Angle of deviation =zero Since INCIDENT ray is parallel to EMERGENT ray. Hence, the correct OPTION is (d).