Question

If a magnification of, –1 (minus 1) is obtained by using a converging lens, then the object has to be placed:
(a) within f
(b) at 2f
(c) beyond 2f
(d) at infinity

Answer 1

 At 2f

When an object is placed at 2f, the size of the image formed will be equal to the size of the object. Therefore, we get a magnification of 1.