Question

Which of the following form(s) a virtual and erect image for all positions of the object?
(This question has multiple correct options)
A. Convex lens
B. Concave lens
C. Convex mirror
D. Concave mirror

Answer 1

Hint: To solve this type of question we must keep in mind that the reflecting surfaces which are diverging in nature generally give virtual and erect and diminished images. So now we have to find that out of these four reflecting surfaces which are diverging in nature.

Complete answer:
Convex lens and concave mirror, both of them give a real and inverted image when the object is kept farther than the focal length from the mirror or lens because they are converging in nature. They converge the light rays coming from an object to a particular point and a real and inverted image is formed. On the other hand, Concave lenses and convex mirrors are diverging in nature. Therefore, the refracted/reflected rays do not meet at any particular point and they are virtually produced to a point where they meet. Therefore, we get a virtual image being formed and a virtual image is always erect.
So, the correct answer to the given question is that only a concave lens and convex mirror form a virtual and erect image for all positions of the object. Hence, the correct options are B and C.

Note: A concave lens is a lens that possesses both the surfaces that curve inwards. It is a diverging lens, meaning that it spreads out light rays that have been refracted through it. A concave lens is thinner at its centre and wider at its edges, and is used to correct short-sightedness or myopia. Convex lenses are thicker at the middle and thinner at the edges. The rays of light that pass through these lenses are brought closer together that means they converge. A curved mirror is a mirror with the curved reflecting surfaces. If the inner side of the spherical mirror is reflecting then it is called a concave mirror and if the outer side of the spherical mirror is reflecting, it is called a convex mirror. Image.