Question

Plz answer fast....Will be marking as brainliest​

Answer 1

Explanation:

f= -20cm

1/f= -1/20

height of image =3 height of object

hi/ho= v/u

3ho/ho=v/u

3=v/u

3u=v

1/f=1/v-1/u

-1/20=1/3u-1/u

-1/20= -2/3u

3u=40

u=40/3

so object distance should be 40/3cm