A person can see objects clearly between \(1~\text{m} \)and \(3~\text{m}. \). The power of the lens required to correct near point will be:
1. \(-2.5~\text{D}\)
2. \(3~\text{D}\)
3. \(+ 1.5~\text{D}\)
4. \(- 1.75~\text{D}\)

In the case of a compound microscope, the image formed by the objective lens is:

In the following diagram, what is the distance \(x\) if the radius of curvature is \(R= 15​​\text{cm}?\)

In the diagram shown below, the image of the point object \(O\) is formed at \(l\) by the convex lens of focal length \(20~\text{cm},\)  where \(F_1\) and \(F_2\) are foci of the lens. The value of \(x'\) is:
        

A glass slab is placed with the right-angled prism as shown in the figure. The possible value of \(\theta\) such that light incident normally on the prism does not pass through the glass slab is:

A graph is plotted between the angle of deviation \(\delta\) in a triangular prism and the angle of incidence as shown in the figure. Refracting angle of the prism is:

Three identical thin convex lenses are kept as shown in the figure. A ray passing through the lens is shown. The focal length of each lens is:

     
1. \(2\)
2. \(1.5\)
3. \(1.75\)
4. \(1.3\)

An astronomical telescope has angular magnification of \(20\) in its normal adjustment. Focal length of eyepiece is \(4\) cm. Distance between objective and eyepiece is: