If the critical angle for total internal reflection from a medium to vacuum is \(45^{\circ}\), the velocity of light in the medium is: 

1.	\(1.5\times10^{8}~\text{m/s}\)	2.	\(\dfrac{3}{\sqrt{2}}\times10^{8}~\text{m/s}\)
3.	\(\sqrt{2}\times10^{8}~\text{m/s}\)	4.	\(3\times10^{8}~\text{m/s}\)

A rod of length \(10~\text{cm}\) lies along the principal axis of a concave mirror of focal length \(10~\text{cm}\) in such a way that its end closer to the pole is \(20~\text{cm}\) away from the mirror. The length of the image is:
1. \(15~\text{cm}\) 
2. \(2.5~\text{cm}\)
3. \(5~\text{cm}\)
4. \(10~\text{cm}\)

Suppose that the lower half of the concave mirror’s reflecting surface in the given figure is covered with an opaque (non-reflective) material. What effect will this have on the image of an object placed in front of the mirror?

The near point of a hypermetropic person is \(75~\text{cm}\) from the eye. What is the power of the lens required to enable the person to read clearly a book held at \(25~\text{cm}\) from the eye?
1. \(+2.67~\text{D}\) 
2. \(-1.25~\text{D}\) 
3. \(-2.67~\text{D}\)
4. \(+1.25~\text{D}\)

To increase the angular magnification of a simple microscope, one should increase:

A ray is incident at an angle of incidence \(i\) on one surface of a small angle prism (with the angle of the prism \(A\)) and emerges normally from the opposite surface. If the refractive index of the material of the prism is $\mathrm{}$\(\mu,\) then the angle of incidence is nearly equal to: