The power of a converging lens is 4.5 D and that of a diverging lens is 3 D. The power of the combination of these lenses is:
+1.5 D
Given: Power of the converging lens (convex lens) P1=+4.5 D
Power of the diverging lens (concave lens) P2=−3 D
Power of the combination of these lenses, P=P1+P2
On substituting values, we get P=(+4.5 D)+(−3 D)=+1.5 D.
Therefore, the resultant power of the combination will be +1.5 D.