An observer to the right of the mirror-lens combination shown in Figure sees two real images that are the same size and in the same location. One image is upright and the other is inverted. Both images are `1.50` times larger than the object. The lens has a focal length of `10.0 cm`. The lens and mirror are separated by `40.0 cm`. Determine the focal length of the mirror. Do not assume that the figure is drawn to scale.

Options

A. `35//6 cm`
B. `2cm`
C. `20 cm`
D. `10 cm`

Answer

B

Explanation

The object must be located at the centre of the curvature of the mirror for this to happen.
For the inverted image formed directly by the lens we can write
`(1)/(v) - (1)/(u) = (1)/(10), (v)/(u) = -(3)/(2)`