Question

A photograph of a horse is taken by a camera whose lens has been painted with black straps. The photograph will be of a:
A. horse with the same brightness as would have been if the lens were not painted.
B. Zebra with the same brightness as would have been if the lens was not painted.
C. horse with less brightness as would have been if the lens was not painted.
D. Zebra with less brightness as would have been if the lens was not painted.

Answer 1

Hint: camera is an application instrument that is used to capture images. Mostly convex lenses are used in the camera. This is because the convex lens can make a small image of large objects. When a lens is completely painted black from one side the other side of the lens works as a reflecting surface.

Complete step by step answer:
The camera which captures images of an object placed at a large distance we consider convex lenses. When a convex lens is covered with some straps to opaque the lens, the no of rays passing through it reduces.
When the image is formed by a huge number of rays coming from the object. If any part of the lens is covered, the image will be formed but the brightness of the image will be less as compared to the image formed by the lens without any type of coating.
Thus, if a photograph of a horse is taken by a camera with a lens that is painted with black stripes, the image will be of a horse with less brightness as compared to the image formed by the lens which was not painted.

So, the correct answer is “Option C”.

Additional Information: Convex lenses are used in many applications where we have to form a small image of a large object. It is used in rear view mirrors in vehicles, traffic controlling points, Shops, malls.

Note: In a lens pure refraction of rays of light occurs. But when we shade some of its sections, the shaded parted reflects some rays of light that are interacting with the shaded part of the lens. Thus, in such cases both reflection and reflection of light takes place.