If a light ray is incident normally on face \(AB\) of a prism, then for no emergent ray from second face \(AC\):
\([\mu \rightarrow\) refractive index of glass of prism]

   

1.	\(\mu=\frac{2}{\sqrt{3}}\)	2.	\(\mu>\frac{2}{\sqrt{3}}\)
3.	\(\mu<\frac{2}{\sqrt{3}}\)	4.	\(\mu\) can have any value.

A lens forms an image of a point object placed at distance \(20\) cm from it. The image is formed just in front of the object at a distance \(4\) cm from the object (and towards the lens). The power of the lens is:
1. \(-2.25\) D
2. \(1.75\) D
3. \(-1.25\) D
4. \(1.4\) D

The distance between the object and its real image formed by a concave mirror is minimum when the distance of the object from the centre of curvature of the mirror is: [\(f\rightarrow\) focal length of the mirror]
1. Zero
2. \(\frac{f}{2}\)
3. \(f\)
4. \(2f\)

A point object \(O\) is placed at a distance \(20\) cm from a biconvex lens of the radius of curvature \(20\) cm and \(\mu=1.5.\) The final image produced by lens and mirror combination will be at:

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 \(R= 15\) cm?

     
1. \(30\) cm
2. \(20\) cm
3. \(15\) cm 
4. \(10\) cm 

In the diagram shown below, the image of the point object \(O\) is formed at \(l\) by the convex lens of focal length \(20\) 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: