Question

a concave lens has focal length 75cm at what distance should the object from the lens be placed so that it forms an image at 10cm from the lens? also find the magnification produce by the lens

Answer 1

1/v+1/u=1/f
1/-10 +1/-75=1/u
-150/3=u
u= -11.5cm
m= v/u
m= 10/11.5
m=0.7