UPSC CDS 2 2019 GK Paper

Concept:Magnification is the ratio of the image size (observed size) to the object size (actual size).Explanation:Magnification tells how many times larger or smaller the image appears compared to the object.It is defined as: $m = \frac{\text{Image size}}{\text{Object size}} = \frac{\text{Observed size}}{\text{Actual size}}$.In microscopy, the observed size is the size of the image seen through the lens.Therefore, magnification $= \frac{\text{Observed size}}{\text{Actual size}}$.Option A is the reciprocal (actual/observed).Option C is subtraction, not ratio.Option D is product, not applicable.Answer:B. observed size of specimen/actual size