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Q.
If lower half of a concave mirror is blackened, then
Ray Optics and Optical Instruments
Solution:
If lower half of a concave mirror is blackened, then image will now only half of the object, but taking the laws of reflection to be true for all points of the remaining part of the mirror, the image will be that of the whole object.
However, as the area of the reflecting surface has been reduced, the intensity of the image will be low i.e., half.