Question

A Convex lens of focal lenth 10 cm is placed at a distance of 12 cm from a wall,Calculate the distance from the lens where an object be placed so as to form its distinct real images on the wall. plz solve .............

Answer 1

Since image is formed on the wall, the image distance is the distance between lens and the wall.
v = +12 cm
f = +10 cm
u = ?

$from\ lens\ formula\\ \\ \frac{1}{v} - \frac{1}{u} = \frac{1}{f} \\ \\ \frac{1}{12} - \frac{1}{u} = \frac{1}{10} \\ \\ \frac{1}{u} = \frac{1}{12}-\frac{1}{10}= \frac{5-6}{60} = \frac{-1}{60} \\ \\ u=\boxed{-60\ cm} \\ \\ so\ object\should\ be\ placed\ \underline{60cm}\ from\ the\ lens.$

Answer 2

60cm is tthe answer  as per ur q