Question

Which of the following is not correct about Galilean Telescope?
A. Its objective is convex lens
B. Its eyepiece is a concave lens
C. The final image is erect
D. The final image is real

Answer 1

Hint:In order to solve this question we first discuss about convex lens which is defined as convex lens are those lens having thicker in middle than edges and its property is to focus parallel light on a particular point known as focal point on the other side of lens.So the image it forms is real on the other hand concave lens is defined as those lens which have thicker edges then center and its property is to diverge parallel beam of light such that it appears to come from a point known as focal point on same side of lens, so the image it forms is virtual.

Complete answer:
Galilean Telescopes are astronomical telescopes that have biconvex and biconcave lenses.Its eyepiece is concave lens and its objective is convex lens so convex lens focuses beam on concave lens as concave lens is placed at focal point so the final image that formed is virtual, erect and magnified. The image is not real. The reason behind this is that a concave lens diverges a parallel beam of light so the final image formed behind the screen is a virtual image.

Hence the correct option is D.

Note:It must be remembered that used concave and convex lens are bi in nature that means they can converge and diverge lights from both side also image is magnified whose magnification increases if the object is near to telescope so from this we can found out distance of object and idea of its size.