Question

In a compound microscope, what is the nature of intermediate image?

Answer 1

Hint: In order to find the correct answer to this very interesting question it is important to think about the basic working of a compound microscope before proceeding further. A compound microscope has two lenses in which the focal length of one is smaller than the other. If we could find the result of this curious anomaly we can arrive at the right answer.

Complete answer:
When we study the construction and working of a compound microscope in detail we see that the focal length of the objective lens is smaller than the object distance. As a result of this, the image formed will have the properties of when an object is placed beyond the principal focus. Thus, the image will be real, inverted and magnified. This magnification is necessary as the principal working of a compound microscope is to form highly magnified images of objects that cannot be seen through the lens of the naked eye. Thus, the intermediate image formed by a compound microscope is real, inverted and magnified.

Additional Information:
The focal length of an objective lens in a compound microscope is kept short deliberately. This is because the magnifying power of a compound microscope is inversely proportional to the focal length of the objective lens. Hence, we see that the smaller the focal length of the objective lens is kept the higher will be the magnifying power of the compound microscope. On the other hand, if the focal length of the objective lens is kept large, the resolving power will also increase.

Note: The image formed by a single convex lens is always real and inverted if placed beyond the focus. However, if the object is placed between the focus of the lens and the optical center of the lens, then the image will be virtual and erect. The convex lens is a converging lens and so converges all the rays parallel to the principal axis of the lens and converges them into a single point called focus.