Question

1. For what position of the object magnification of convex lens is -1
(minus one)?
​

Answer 1

If the object is placed at Centre of curvature, then the image is formed at second Centre of curvature on other side of lens, and is inverted & same size of the object.

Thus, We can say that,

$\small {\text{Height of object}}\red{=}{\text{--(Height of image)} }\\ \\ \because \small{\text{The object is placed at upside of principal axis}} \: \& \: \\ \small\text{{ the image is at below of principal axis}}$

Hence,

• It is concluded that magnification for convex lens is (-1) if the object is at centre of curvature