Question

Question 20
Identify the device used as a spherical mirror or lens in following cases, when the image formed is virtual and erect in each case.

(a) Object is placed between device and its focus, image formed is enlarged and behind it.

(b) Object is placed between the focus and device, image formed is enlarged and on the same side as that of the object.

(c) Object is placed between infinity and device, image formed is diminished and between focus and optical centre on the same side as that of the object.

(d) Object is placed between infinity and device, image formed is diminished and between pole and focus, behind it.

Answer 1

(a) Concave mirror – In a concave mirror, if the object is placed between the mirror and the focus then the image formed is enlarged, erect and virtual.
(b) Convex lens – In a convex lens, if the object is placed between the lens and its focus then the image formed is enlarged, erect, virtual and on the same side as that of the object.
(c) Concave lens - In a concave lens, if the object is placed at infinity, the image formed is highly diminished, virtual, erect and between focus and optical centre on the same side as that of the object.
(d) Convex mirror- In a convex mirror, if the object is placed at infinity, the image formed is highly diminished, virtual, erect and between pole and focus.