Question

In which of the following spherical mirrors is the magnification of the image always less than 1?

• A. Convex
• B. Plane
• C. Concave
• D. All of these

Hint:

Which mirror always gives a virtual, erect and diminished image regardless of object position?

Answer 1

The Correct Option is A

Step 1: Magnification is \( m = \dfrac{\text{image height}}{\text{object height}} \). If \( |m| < 1 \) the image is diminished (smaller than the object).

Step 2: A convex mirror always forms a virtual, erect and diminished image for any real object, no matter where the object is placed. So its magnification is always \( |m| < 1 \).

Step 3: A concave mirror can form magnified images (for example when the object lies between the focus and the pole, or between C and F), so \( |m| \) can be greater than 1. A plane mirror always gives \( |m| = 1 \), an image equal in size, not less than 1.

Step 4: Only the convex mirror satisfies the condition, so option 1 is correct, and option 4 (all of these) is therefore wrong.

\[\boxed{\text{Convex mirror}}\]