Question

How will the magnitude of magnification change if an object placed at center of curvature is moved towards focus in concave mirror?

• A. It decreases
• B. It increases
• C. It remains constant
• D. It becomes equal to infinity

Answer 1

The correct option is B

It increases

(1)

(2)

(3)

As the object moves towards focus, the height of the image increases as shown in these ray diagrams.

We know that magnification (m) = $\frac{\text{height of image}}{\text{height of object}}$.

As the height of the image increases, the numerator increases, which in turn leads to the increase in the magnitude of magnification.