Question

At what distance should an object be placed from convex lens of focal length 9 cm to obtain an image at 18 cm from it ? What will be the magnification produced in this case ?​

Answer 1

f = 18 cm

v = 24 cm

Lens formula : 1/v – 1/u = 1/f

1/24 – 1/u = 1/18

1/u = 1/24 – 1/18

1/u = (3 – 4)/72 = -1/72

u = -72 m