An object 1 cm high produces a real image 1.5 cm high, when placed at a distance of
Given :
Object height, hi = 1 cm
Image height, ho = - 1.5 cm ( given to be real )
Object distance, u = -15 cm
To Find :
Position of the image, v
Focal length of the mirror, f
magnification m = hi/h0 = -v/u
(-1.5)/1= - (v)/(- 15)
v = - 22.5 cm
the image is 22.5 cm in front of the mirror
1/v + 1/u = 1/f
1/-22.5 + 1/-15 =1/f
-2 -3 / 45 =1/f
-5/45=1/f
f= - 9
the focal length is 9 cm