Question

an object of height 6 cm is placed at a distance of 20cm in front of a concave lens of a power minus 8 find the size of the image ko​

Answer 1

Given :    u=−10 cm              f=−5 cm                ho=6 cm

Using lens formula :       v1−u1=f1

∴      v1−(−10)1=−51              

⟹v=−310=−3.33  cm     (- sign shows that image is virtual)

Also   m=hohi=uv

∴   6hi=−103−10                

⟹hi=+2 cm   (+ sign shows that image is erect)