Question

When a real object is placed 25 cm from a lens, a real image is formed. Mark the correct statement(s) from the following.
This question has multiple correct options.

A.) The lens is a converging lens
B.) The images may be magnified or diminished
C.) The focal length of the lens is less than 25 cm
D.) The focal length of the lens may be greater than 25 cm

Answer 1

Hint: Study about images formed by lenses. Learn the basics of concave and convex lenses and try to remember the formation of image position with the object position for both types of lenses.

Complete step by step solution:
Now, we are given that the image formed is a real image.
We know that for a real image to be formed we need a convex lens. We don’t get real images for a concave lens. So, this lens is a convex lens or a converging lens.

Now, we know that for a convex lens we can get a real image only if the object is placed between infinity and the focus. If the object is between the focus and pole no real image will be formed.

Since the object is at 25 cm from the lens, the focal length of the object should be less than 25 cm because to form a real image the object must be at a larger distance than the focal length.

Now, depending on the position of the object from infinity to the focus, the magnification may be greater than 1 or less than 1. So, the image may be magnified or diminished.
So, the correct options are (A), (B), (C) .

Note: A convex lens is also called a converging lens because it converges light rays to the focus of the lens. A concave lens is also called a diverging lens because it diverges the light rays and it seems to come out of the focus of the lens.