Question

On moving from focus towards the pole, the magnification in a concave mirror:

• A. increases
• B. decreases
• C. remains constant
• D. none of these

Hint:

In a concave mirror, moving an object from the focus towards the pole increases magnification, making the image larger and more upright.

Answer 1

The Correct Option is A

Step 1: Understanding magnification in a concave mirror. The magnification (\( m \)) of a concave mirror is given by: \[ m = \frac{-v}{u} \] where:
- \( v \) is the image distance,
- \( u \) is the object distance.
For a concave mirror:

- When the object is beyond the center of curvature (\( C \)), the image is real, inverted, and smaller (\( |m|<1 \)).
- When the object is at \( C \), the image is of the same size (\( |m| = 1 \)).
- When the object is between \( C \) and \( F \) (focus), the image is real, inverted, and magnified (\( |m|>1 \)).
- When the object is at \( F \), the image is formed at infinity.
- When the object is between \( F \) and \( P \) (pole), the image is virtual, upright, and highly magnified.
Step 2: Behavior of magnification as the object moves from \( F \) to \( P \).
- When the object moves from the focus towards the pole, the image remains virtual and magnified.
- The magnification increases as the object gets closer to the mirror.
- At the pole, the magnification tends to infinity.
Step 3: Conclusion.
Since magnification increases as the object moves towards the pole, the correct answer is (A) increases.