Question

State True or False :
For correction of defects in the human eye, spectacles form virtual images only.
A) true
B) false.

Answer 1

Hint: Our human eye forms a real and inverted image at the back of the retina. When we put on a spectacles for recorrecting any diseases like myopia or hypermetropia or presbyopia, the lens forms a different image to that of the image formed by the eye.

Complete step-by-step answer:
We need to find the nature of image formed by the lenses we use for correcting defects in our eye,
First, let us consider the concave lens.
Concave lens is used to correct the near sightedness. It helps the eye by moving the image formed back to the retina and making it clear for the viewer. A concave lens is a lens that possesses at least one surface that curves 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 than at its edges, and is used to correct the eye disease called myopia. It forms a virtual image to bring the image closer from infinity to far point.
Next, let us discuss convex lenses. A convex lens is used to correct hypermetropia. When a convex lens of suitable power is placed in front of a hypermetropia eye, then diverging rays of light coming from nearby objects are first converged by a convex lens. Due to this, the convex lens forms a virtual image of nearby objects.

Therefore, both the lenses form virtual images to correct the defects in the human eye.

Note: Myopia is a defect where some people cannot see the objects close to them clearly, but not the objects that are too far away. It is corrected using a concave lens. Hypermetropia is the defect where near objects cannot be seen. Hence, a convex lens is used.