Question

the distance between the object and image is found to be 40cm if the magnification of the image is -1 calculate the focal length of the lens.
​

Answer 1

Explanation:

u + v = 40

vu = 3

v = 3u

u + 3u = 40

4u = 40

u = 10cm

v = 3u = 30cm

f = uvu+v=10(30)10+30=30040

= 7.5 cm

if it helps please mark as brainliest