Human Eye and C...

A man can see clearly up to $$3\ \textit{metres}$$. Prescribe a lens for his spectacles so that he can see clearly up to $$12\ \textit{metres}$$

A person cannot see distinctly at the distance less than one metre. Calculate the power of the lens that he should use to read a book at a distance of $$25\, cm$$

In a glass prism, spectrum is produced due to :

The speeds of red light and yellow light are exactly same 

A normal eye is not able to see objects closer than $$25 \ cm$$ because?

One can not see through fog because:

The rising and setting of sun appear red because of : 

A rainbow can be seen in the sky

The change that occurs in the eye to see the distant objects cleary is

The least distance of distinct vision for a young adult with normal vision is