Question

With respect to infinity, 2F, F and optical centre of a convex lens, when it is used as:

1. Objective lens of a telescope.
2. For erecting an image formed by a telescope.
3. Objective lens of photographic camera.
4. Object lens of a slide projector.
5. Objective lens of a search light.
6. Objective lens of a simple microscope.

Answer 1

1. The object is located at infinity.
2. The object is placed at 2F to create an identical inverted image that rectifies the view.
3. The object is positioned beyond 2F to capture a real, inverted, and diminished image onto the sensor.
4. The object is positioned between F and 2F to cast a real, inverted, and highly magnified image onto a distant screen.
5. The object is placed exactly at the focus F to produce a powerful, parallel beam of light that travels long distances.
6. The object is placed between F and the optical centre to view a highly magnified, virtual, and upright image.