Answer:
7.50 cm
Step-by-step explanation:
The formula
1/v + 1/u = 1/f
Is used.
where.
u is the object distance.
v is the image distance.
f is the focal length of the lens.
1/v + 1/15 = 1/5
1/v = 1/5 - 1/15
1/v = (3-1)/15
1/v = 2/15
2v = 15
V = 15/2
V = 7.5 cm
For focal length, f in lens is always taken as negative for concave and positive for convex. ... And for image distance, V in lens it is taken as positive in Convex lens since image is formed on +X side. It is taken as negative in Concave lens since image is formed in -X side of the Cartesian.