TIR

Q.

When the light goes from an optically denser to an optically rarer medium, it always bends _____ the normal.

Q.

Consider the situation shown in figure. Find the maximum angle $\theta$ for which the light suffers total internal reflection at the vertical surface.

1. $si{n}^{-1}\left(4/5\right).$

2. $si{n}^{-1}\left(1/4\right).$

3. $si{n}^{-1}\left(3/4\right).$

4. None of the above.

Q. The velocity of light in a medium is half its velocity in air. If ray of light emerges from such a medium into air, the angle of incidence, at which it will be totally internally reflected, is

1. ${15}^{\circ }$
2. ${30}^{\circ }$
3. ${25}^{\circ }$
4. ${35}^{\circ }$

Q. In total internal reflection, laws of reflection hold true.

1. True
2. False

Q. Light is incident normally on face AB of a prism as shown in figure. A liquid of refractive index $\mu$ is placed on face AC of the pr 9 is m. The prism is made of glass of refractive index $\frac{3}{2}$. The limits of $\mu$ for which total internal reflection takes place on face AC is

1. $\mu >\frac{\sqrt{3}}{2}$
2. $\mu <\frac{3\sqrt{3}}{2}$
3. $\mu >\sqrt{3}$
4. $\mu <\frac{\sqrt{3}}{2}$

Q. Which of the following conditions hold true if the ray (shown in figure) always undergo total internal reflection at the surface $\text{AC}$. The critical angle between prism and air is $i_c$.

1. $A>i_c$
2. $A<i_c$
3. $A>2i_c$
4. $A<2i_c$

Q. The wavelength of light in two liquids 'x' and 'y' is 3500 $\stackrel{\circ }{A}$ and 7000 $\stackrel{\circ }{A}$, then the critical angle of x relative to y will be

1. ${60}^{\circ }$
2. ${45}^{\circ }$
3. ${30}^{\circ }$
4. ${15}^{\circ }$

Q. A light ray from air is incident (as shown in figure) at one end of a glass fiber (refractive index $\mu =1.5$) making an incidence angle of ${60}^{\circ }$ on the lateral surface, so that it undergoes a total internal reflection. How much time would it take to traverse the straight fiber of length 1 km

1. $3.33\mu sec$
2. $6.67\mu sec$
3. $5.77\mu sec$
4. $3.85\mu sec$

Q. A fish looking from within water sees the outside world through a circular horizon. If the fish is $\sqrt{7}m$ below the surface of water, then the radius of the circular horizon will be

1. $1m$
2. $2m$
3. $3m$
4. $4m$

Q. A monochromatic light is incident from air on a refracting surface of a prism of angle ${75}^{\circ }$ and refractive index $n_0=\sqrt{3}.$ The other refracting surface of the prism is coated by a film of material of refractive index $n$ as shown in figure. The ray of light suffers total internal reflection at the coated prism surface for an incidence angle of $\theta \le {60}^{\circ }.$ The value of $10n^2$ is

Q. A beam of light consisting of red, green and blue colours is incident on a right angled prism. The refractive index of the material of the prism for the red, green and blue colours are $1.39$, $1.44$ and $1.47$ respectively. The prism will

1. separate the red colour from the green and blue colours
2. separate the blue colour from the red and green colours
3. separate all the three colours from one another
4. not separate the three colours at all

Q. Light is incident normally on face $AB$ of a prism as shown in figure. A liquid of refractive index $\mu$ is placed on face $AC$ of the prism. The prism is made of glass of refrctive index $3/2$. The limits of $\mu$ for which total internal reflection takes place on face $AC$ is

1. $\mu >\frac{\sqrt{3}}{2}$
2. $\mu <\frac{3\sqrt{3}}{4}$
3. $\mu >\sqrt{3}$
4. $\mu <\frac{\sqrt{3}}{2}$

Q. For the given incident ray as shown in figure, for the condition of total internal reflection of this ray, the minimum refractive index of prism will be:-

1. $\frac{\sqrt{3}+1}{2}$
2. $\frac{\sqrt{2}+1}{2}$
3. $\sqrt{\frac{3}{2}}$
4. $\sqrt{\frac{7}{6}}$

Q. A ray of light is incident at an angle i from denser to rare medium. The reflected and the refracted rays are mutually perpendicular. The angle of reflection and the angle of refraction are respectively r and r’, then the critical angle will be

1. $si{n}^{-1}\left(sinr\right)$
2. $si{n}^{-1}\left(tan{r}^{\prime }\right)$
3. $si{n}^{-1}\left(tani\right)$
4. $ta{n}^{-1}\left(sini\right)$

Q. For the given incident ray as shown in figure, for the condition of total internal reflection of this ray, the minimum refractive index of prism will be:-

1. $\frac{\sqrt{3}+1}{2}$
2. $\frac{\sqrt{2}+1}{2}$
3. $\sqrt{\frac{3}{2}}$
4. $\sqrt{\frac{7}{6}}$

Q. Dispersion without deviation is produced by two thin (small angled) prisms which are combined. One prism has angle $6^{\circ }$ and refractive index $1.52$. If the other prism has an angle $4^{\circ }$, what is its refractive index ?

1. $1.64$
2. $1.48$
3. $1.78$
4. $1.17$

Q. Dispersion without deviation is produced by two thin (small angled) prisms which are combined. One prism has angle $6^{\circ }$ and refractive index $1.52$. If the other prism has an angle $4^{\circ }$, what is its refractive index ?

1. $1.64$
2. $1.17$
3. $1.78$
4. $1.48$

Q.

Light is going from some denser medium to air. The refractive index of the medium is 1.7. Calculate the angle of incidence, such that if it is further increased, total internal reflection will occur in medium I.

1. $si{n}^{-1}\left(\frac{1}{\sqrt{3}}\right)$
2. $si{n}^{-1}\left(\frac{1}{\sqrt{2}}\right)$
3. $si{n}^{-1}\left(\frac{1}{\sqrt{5}}\right)$
4. Such an angle of incidence can't be calculated