A convex lens of focal length f1 and a concave lens of focal length f2 are placed in contact. The focal length of the combination is_____________?

Related Mcqs:

1. Two convex lenses of equal focal length f are placed in contact the resultant focal length of the combination is______________?

   A. zero B. focus C. 2 f D. f/2...

2. Dioptre power of an concave lens of 10 cm focal length is_______________?

   A. 10 dioptre B. 10 dioptre C. 1 / 10 dioptre D. 1 / 10 dioptre...

3. A convex lens acts as a diverging lens if the_________________?

   A. object is beyond C B. if the object is with in C C. if the object is within f D. both B and C...

4. The minimum distance between an object and its real image in a convex lens is_____________?

   A. 2 f B. 2.5 f C. 3f D. 4f...

5. Power of a lens is one diopter if its focal length is

   A. 1 meter B. 2 meter C. ½ meter D. ¼ meter Submitted by: Rizwan Ayub Saadi...

6. The power of a concave lens is_______________?

   A. real B. virtual C. positive D. negative...

7. If a convex lens of large aperture fails to converge the light rays incident on it to a single point, it is said to suffer from______________?

   A. chromatic aberration B. spherical aberration C. both spherical and chromatic D. distortion...

8. A convex lens gives a virtual image only when the objects lies_________________?

   A. between principal focus and center of curvature B. beyond 2 f C. at the principal focus D. between principal focus and optical center...

9. If an object is placed away from 2f of a converging lens then the image will be_______________?

   A. real and erect B. virtual and erect C. real and inverted D. virtual...

10. A person wears spectates with concave lenses. It means that normally (when not using glasses), the image of distant objects is focused in his eyes:

    A. behind the retina B. in front of the retina C. on the retina D. on the blind spot Submitted by: Abid Hussain...