Thin lenses and optical instruments

Question 1 of 10

An object is placed 60 cm from a converging lens of focal length 20 cm. Find the image distance.

Question 2 of 10

Explain short sight and long sight, with diagrams, and state how each is corrected.

Question 3 of 10

A magnifying glass uses a diverging lens.

Question 4 of 10

The part of the eye that controls the amount of light entering is the

Question 5 of 10

An object is placed 15 cm from a converging lens of focal length 10 cm. (a) Calculate the image distance. (b) Calculate the magnification. (c) State the nature of the image. (d) Calculate the power of the lens.

Question 6 of 10

In the human eye, focusing on objects at different distances is done by

Question 7 of 10

Long sight (hypermetropia) is corrected using a

Question 8 of 10

A converging lens of focal length 12.5 cm has a power of ___ dioptres.

Question 9 of 10

In a compound microscope, the final image is

Question 10 of 10

The power of a lens is