Question

Which of the following statements is incorrect?
(A) For a convex mirror, magnification is always negative.
(B) For all virtual images formed by a mirror, magnification is positive.
(C) For a concave lens, magnification is always positive.
(D) For real and inverted images, magnification is always negative.

Hint:

Concave lenses always form virtual, upright, and diminished images, so their magnification is negative.

Answer 1

We need to evaluate the given statements about magnification for different mirrors and lenses.

1. Understanding the Concepts:

Magnification: The magnification of an image is the ratio of the image's height to the object's height. It is given by the formula \( m = \frac{h_i}{h_o} \), where \( h_i \) is the image height and \( h_o \) is the object height. A positive magnification means the image is upright, and a negative magnification means the image is inverted.

2. Analyzing the Statements:

Statement (A): For a convex mirror, magnification is always negative.
This statement is incorrect. For a convex mirror, the image formed is always virtual, upright, and smaller than the object. The magnification for a convex mirror is always positive, not negative.

Statement (B): For all virtual images formed by a mirror, magnification is positive.
This statement is correct. Virtual images formed by mirrors, such as in concave mirrors or convex mirrors, are always upright, resulting in a positive magnification.

Statement (C): For a concave lens, magnification is always positive.
This statement is correct. A concave lens always forms a virtual, upright image, which results in a positive magnification.

Statement (D): For real and inverted images, magnification is always negative.
This statement is correct. Real and inverted images, which are formed by concave mirrors or convex lenses, always have a negative magnification.

3. Conclusion:

The incorrect statement is Statement (A): "For a convex mirror, magnification is always negative." This is false because the magnification for convex mirrors is always positive.

Final Answer:

The incorrect statement is (A) For a convex mirror, magnification is always negative.