Question

A convex lens forms a real image 4 times magnified when placed at a distance of 6 cm from the lens. Calculate the focal length of the lens​

Answer 1

Answer:

m = 4 u = 6cm v = ? Read more on Sarthaks.com - https://www.sarthaks.com/280849/convex-forms-image-times-magnified-placed-distance-from-lens-calculate-focal-length-lens

Explanation:

m = 4 u = 6cm v = ? Read more on Sarthaks.com - https://www.sarthaks.com/280849/convex-forms-image-times-magnified-placed-distance-from-lens-calculate-focal-length-lens

Answer 2

Answer:

Magnification (m) = v/u

-4 = 60/u

So, u = 60/-4 = -15cm

1/f = 1/v - 1/u = 1/60+1/15 = 5/60

Thus, f = 60/5 = 12 cm = 0.12 m

P = 1/f = 1/0.12 = 8.33 D