Human Eye and C...

A student sitting on the last bench can read the letters written on the blackboard but is not able to read the letters written in his textbook. Which of the following statements is correct?

Fine beam of light entering through a small hole in a dark room illuminates the particles in its path. Identify the effect associated with this process.

 A prism ABC (with BC as base) is placed in different orientations. A narrow beam of white light is incident on the prism. In which of the following cases, after dispersion, the third colour from the top corresponds to the colour of the sky?

The clear sky appears blue because:

Which of the following statements is correct regarding the propagation of light of different colors of white light in air?

The danger signals installed at the top of tall buildings are red in colour. These can be easily seen from a distance because among all other colours, the red light:

A person needs a lens of power -4.5 D for correction of her vision. What kind of defect in vision is she suffering from?

Why is the colour of the clear sky blue?

How will you use two identical prisms so that a narrow beam of white light incident on one prism emerges out of the second prism as white light? 

When do we consider a person to be myopic?