Question

find the value of focal length if object distance is -15 cm and image distance is - 60 CM​

Answer 1

1/v+ 1/u=1/f

1/-60+1/-15= 1/f

1/60-1/-15=1/f

1+4/60=1/f

-5/60=1/f

-5f=60

f=60/-5

f=-12cm