Question

2. A lens of focal length 12cm forms an erect image, three times the size of the
object. The distance between the object and image is;
a.8cm
b. 16cm
c. 24cm
d.36cm​

Answer 1

Answer:

16cm

Magnification , m=uv 

3=uv 

⇒v=3u 

Lens formula : v1−u1=f1 

3u1−u1=121 

3u−2=121 

⇒u=−8cm 

v=3×−8=−24cm 

Distance between object and image =u−v=−8−(−24)=−8+24=16cm