Question

Identify the wrong sign convention

• A. The magnification for virtual image formed by a convex lens is positive
• B. The magnification for real image formed by a convex lens is negative
• C. The height measured normal to the principal axis upwards is positive
• D. The distances measured in the direction of incident light is positive
• E. The magnification for virtual image formed by a concave lens is negative

Hint:

Virtual image = erect = positive magnification.

Answer 1

Answer: (E)

Understanding the Concept: Sign convention in optics:
• Upward heights → positive
• Along incident light → positive
• Real image → inverted → negative magnification
• Virtual image → erect → positive magnification

Step 1: Check option (A).
Virtual image by convex lens is erect → magnification positive → correct.

Step 2: Check option (B).
Real image by convex lens is inverted → magnification negative → correct.

Step 3: Check option (C).
Upward direction taken positive → correct.

Step 4: Check option (D).
Distances along incident light are positive → correct.

Step 5: Check option (E).
Concave lens always forms virtual and erect image → magnification is positive, not negative.

Step 6: Final Answer. \[ \boxed{(E)} \]