CBSE Class 12-science Answered
Derive lens formula for concave lens and state lens formula.
Let AB represent an object placed at right angles to the principal axis at a distance greater than the focal length f of the convex lens. The image A1B1 is formed between O and F1 on the same side as the object is kept and the image is erect and virtual.
OF1 = Focal length = f
OA = Object distance = u
OA1 = Image distance = v
But from the ray diagram we see that OC = AB
From equation (1) and equation (2), we get
Dividing throughout by uvf