Assertion: Normal eye cannot see objects clearly which are situated less than $25 \mathrm{cm}$ away from the eye.

Reason: The distance of the retina from the eye lens is less than $25 \mathrm{cm}.$

Assertion: The single lens of a simple microscope sometimes produces coloured image of a white object.

Reason: Single-lens always suffer from chromatic aberration.

Assertion: Street lamp-posts appear to be shorter the farther they are, although, they are all the same height.

Reason: The angle subtended at the eye by far-away posts are shorter.

Assertion: The magnification of a simple microscope $m=\frac{D}{f}$.

Reason: Magnification$=1+\frac{D}{f}.$

Assertion: The magnification of the compound microscope is negative.

Reason: The final image in the compound microscope is inverted with respect to the object.