Question

A convex lens forms an image at twice the distance of the object from the lens. What is the magnification?

• A. 2
• B. -2
• C. 0.5
• D. -0.5

Hint:

In lens formula problems, use proper sign convention. For real inverted images, \( v \) is taken negative for convex lenses.

Answer 1

The Correct Option is A

Step 1: Use magnification formula for lenses. \[ m = \frac{-v}{u} \] Step 2: Given that image is formed at twice the distance of object from lens. 
So, if object distance = \( u \), then image distance \( v = -2u \) (real and on opposite side). 
Step 3: Calculate magnification. \[ m = \frac{-(-2u)}{u} = \frac{2u}{u} = 2 \] So, the magnification is \( 2 \). Since the image is real and inverted, but sign conventions were carefully handled, the magnitude remains positive here.