The filament of a lamp is 80 cm from a screen and a converging lens forms an image of it on a screen, magnified three times. Find the distance of the lens from the filament and the focal length of the lens.
filament of a lamp is 80 cm from a screen = -80 cm
m = 3
using the formula, m = v/u
distance of the lens from the filament = 20 cm ;
Using the lens formula,
f = + 15 cm
19