An object is placed on the principal axis of a lens of power 4.0 D, at a distance of 30 cm. The image formed is

Correct option is B

Given:

Power of the lens is 4.0 D, object distance is 30 cm.

Formula used:

$$\begin{aligned}&\text { } P=\frac{1}{f} \text { }\\\end{aligned}$$​​

Solution:

$$\begin{aligned}&\text { As, } P=\frac{1}{f} \text { we have: }\\&f=\frac{1}{P}=\frac{1}{4}=0.25 \mathrm{~cm}\end{aligned}$$​​​

As focal length is positive and object distance is negative.

Thus, the lens used here is convex lens.

Image formed convex lens it is always real and inverted.

The correct answer is (b) real and inverted.​