When an object is at distances and from the optical centre of a convex lens

PHYSICS · Single correct · AP · Physics 2: Algebra-based · Geometric Optics · Geometric Optics

Problem

When an object is at distances

u_1

and

u_2

from the optical centre of a convex lens, real and virtual images of the same magnification are obtained. The focal length of the lens is (1)

\frac{u_1-u_2}{2}

(2)

u_1+u_2

(3)

\sqrt{u_1u_2}

(4)

\frac{u_1+u_2}{2}