Absolute refractive indices of glass and water are 3/2 and 4/3. The ratio of velocity of light in glass and water will be

1.  4:3

2.  8:7

3.  8:9

4.  3:4

One face of a rectangular glass plate 6 cm thick is silvered. An object held 8 cm in front of the first face, forms an image 10 cm behind the silvered face. The refractive index of the glass is [Consider that light ray returns back in the first medium]

(1) 0.4                     

(2) 0.8

(3) 1.5                     

(4) 1.6

Two transparent slabs have the same thickness as shown. One is made of material A of refractive index 1.5. The other is made of two materials B and C with thickness in the ratio 1:2. The refractive index of C is 1.6. If a monochromatic parallel beam passing through the slabs has the same number of waves inside both, the refractive index of B is

1.  1.1     

2.  1.2

3.  1.3

4.  1.4

The image of point P when viewed from the top of the slabs will be

(1)   2.0 cm above P

(2)   1.5 cm above P

(3)   2.0 cm below P

(4)   1 cm above P

A diverging beam of light from a point source S having divergence angle $\alpha$, falls symmetrically on a glass slab as shown. The angles of incidence of the two extreme rays are equal. If the thickness of the glass slab is t and the refractive index n, then the divergence angle of the emergent beam is:
   

1. Zero                                       

2. $\alpha$

3. ${\sin }^{-1}\left(1/n\right)$                           

4. $2{\sin }^{-1}(1/n)$

A concave mirror is placed at the bottom of an empty tank with face upwards and axis vertical. When sunlight falls normally on the mirror, it is focused at distance of 32 cm from the mirror. If the tank is filled with water $\left(\mu =\frac{4}{3}\right)$ upto a height of 20 cm, then the sunlight will now get focussed at

(1) 16 cm above water level

(2) 9 cm above water level

(3) 24 cm below water level

(4) 9 cm below water level

An observer can see through a pinhole the top end of a thin rod of height h, placed as shown in the figure. The beaker height is 3h and its radius h. When the beaker is filled with a liquid up to a height 2h, he can see the lower end of the rod. Then the refractive index of the liquid is

(1) $5/2$                                   

(2) $\sqrt{\left(5/2\right)}$

(3) $\sqrt{\left(3/2\right)}$                               

(4) 3/2

A medium shows relation between i and r as shown. If speed of light in the medium is nc then value of n is

(1)   1.5

(2)   2

(3)   2^–1

(4)   3^–1/2

An air bubble in a glass slab with refractive index 1.5 (near normal incidence) is 5 cm deep when viewed from one surface and  3 cm deep when viewed from the opposite face. The thickness (in cm) of the slab is

(1) 8           

(2) 10

(3) 12         

(4) 16

The frequency of a light wave in a material is 2×10¹⁴ Hz and the wavelength is 5000 Å. The refractive index of the material will be:

1. 1.40

2. 1.50

3. 3.00

4. 1.33