CBSE Class 10 Science 2017 · Paper 31/1/1/C · Question 19

(a) (i) Object between $O$ and $F_1$: the image $A^{\prime }{B}^{\prime }$ is formed on the same side of the lens as the object, farther from the lens than the object; it is virtual and erect, and enlarged. (The refracted rays diverge; their backward extensions meet at $A^{\prime }$.) (ii) Object between $F_1$ and $2F_1$: the image is formed beyond $2F_2$ on the other side of the lens; it is real and inverted, and enlarged. (The refracted rays actually meet at $A^{\prime }$.) (b) A concave lens of the same focal length gives, in both cases, a virtual, erect and diminished image, formed between the focus $F_1$ and $O$ on the same side as the object. In case (i) the nature stays the same (virtual and erect) but the size changes from enlarged to diminished. In case (ii) the nature changes from real and inverted to virtual and erect, and the size changes from enlarged to diminished.