Ravi kept a book at a distance of 10 cm from the eyes of his friend Hari. Hari is not able to read anything written in the book. Give reasons for this?

A man, wearing glasses of power +2D can read clearly a book placed at a distance of 40cm from the eye. The power of the lens required so that he can read at 25cm from the eye is

A short sighted person can see objects most distinctly at a distance of 16 cm . If he wears spectacles at a distance of 1 cm from the eye, what focal length should he have so as to enable him to see distinctly at a distance of 26 cm ? ( c) The person above prefers to remove his spectacles while reading a book. Explain why ? (NCERT Solved Example)

Hari is studying in 6th standard and is interested in science related experiments. While reading simple machines topic from his text book,he started wondering as to which lever a pen belongs to in its writing position? The length of the pen he is using is 14 cm and he holds it at distance of 4 cm from its nib. If the force applied by Hari to write is 0.02 N, the mechanical advantage of the pen is _____ and it is acting as a _____order lever.

In a compound microscope, the objective and eye piece have focal lengths 0.95 cm and 5 cm respectively, and are kept at a distance of 20 cm . The final image is formed at a distance of 25 cm from the eye piece. Calculate the position of the object and the total magnification.

We cannot clearly see an object kept at a distance less than 25 cm from the eye. Give reason

The far point of a myopic eye is 10 cm from the eye. The focal length of a lens for reading at normal distance ( 25cm) is

The near point of a hypermetropic person is 50 cm from the eye. What is the power of the lens required to enable him to read clearly a book held at 25 cm from the eye ?