TIR

Q. In total internal reflection, when the angle of incidence is equal to the critical angle for the pair of media in contact, what will be angle of refraction ?

1. $180°$
2. $0°$
3. $90°$
4. equal to angle of incidence

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.

At what angle should a ray of light be incident on the face of a prism of refracting angle 60° so that it just suffers total internal reflection at the other face? The refractive index of the material of the prism is 1.524.

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 light ray is incident on a transparent sphere of index $=\sqrt{2}$ , at an angle of incidence $={45}^{\circ }$. What is the deviation of a tiny fraction of the ray, which enters the sphere, undergoes two internal reflections, and then refracts out into air?

1. ${270}^{\circ }$
2. ${240}^{\circ }$
3. ${120}^{\circ }$
4. ${180}^{\circ }$

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 is incident, at an incident angle ${\theta }_1$, on the system of two plane mirrors$M_1\text{and}{M}_2$ having an incilination angle ${75}^{\circ }$ between them(as shown in figure). After reflecting from mirror $M_1$ it gets reflected back by the mirror $M_2$ with an angle of reflection ${30}^{\circ }$. The total deviation of the ray will bedegree.

Q. A fish looking up through the water sees outside world contained in a circular horizon. The refractive index of water is $\frac{4}{3}$ and the fish is $12\text{cm}$ below the surface. The radius of this circle in $\text{cm}$ is

1. $36\sqrt{7}$
2. $\frac{36}{\sqrt{7}}$
3. $36\sqrt{5}$
4. $4\sqrt{5}$

Q.

The polarizing angle of glass is ${57}^{\circ }$. A ray of light which is incident at this angle will have an angle of refraction as

1. ${43}^{\circ }$

2. ${25}^{\circ }$

3. ${38}^{\circ }$

4. ${33}^{\circ }$

Q. A ray of light is incident on a ${60}^{\circ }$ prism at the minimum deviation position. The angle of refraction at the first face (i.e., incident face) of the prism is

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

Q. In the figure shown, for an angle of incidence 45^{\circ}at the top surface, what is the minimum refractive index needed for total internal reflection at vertical face

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

Q. Two monochromatic rays of light are incident normally on the face AB of an isosceles right-angled prism ABC. The refractive indices of the glass prism for the two rays '$1$' and '$2$' are 1.35 and 1.45 respectively. Trace the path of these rays after entering through the prism.

Q.

A container contains water up to a height of 20 cm and there is a point source at the centre of the bottom of the container. A rubber ring of radius r floats centrally on the water. The ceiling of the room is 2.0 m in above the water surface.

(a) Find the radius of the shadow of the ring formed on the ceiling if r = 15 cm.

(b) Find the maximum value of r for which the shadow of the ring is formed on the ceiling. Refractive index of water $=\frac{4}{3}$.

Q. Critical angle is minimum for which colour of VIBGYOR?

Q. A ray of light is incident on one face of an equilateral prism. When the angle of incidence is ${90}^{\circ }$, the refracted ray from the first face goes undeviated from the second face. Find the refractive index of the material of the prism.

1. 1.15

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. Critical angle of glass is ${\theta }_1$ and that of water is ${\theta }_2$. The critical angle for water and glass surface would be $({\mu }_g=\frac{3}{2},{\mu }_w=\frac{4}{3})$

1. Less than ${\theta }_2$
   
2. Between ${\theta }_{1}and{\theta }_2$
   
3. Greater than ${\theta }_2$
   
4. Less than ${\theta }_1$

Q.

A beam of unpolarized light is incident on the boundary between $2$ transparent media. If the reflected light is completely plane polarised, how is its direction related to the direction of corresponding refracted light?

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. A light ray in medium (Refractive index $=5/3$) making an angle of ${30}^{\circ }$ with normal, enters another medium. The angle in other medium is ${\sin }^{–1}\left(5/6\right)$. How many minimum degrees the incident angle must be increased such that the ray is completely reflected.

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.

A positive magnification greater than unity indicates

1. Real Image

2. Virtual Image

3. Neither real image nor virtual image

4. Distorted image

Q. How does the angle of minimum deviation of a glass prism vary, if the incident violet light is replaced by red light ? Give reason.

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. ${35}^{\circ }$
4. ${25}^{\circ }$

Q. You are given four sources of light each one providing a light of a single colour – red, blue, green and yellow. Suppose the angle of refraction for a beam of yellow light corresponding to a particular angle of incidence at the interface of two media is ${90}^{\circ }$. State whether the following statement is correct or not. If the source of yellow light is replaced with that of blue light without changing the angle of incidence, the beam of blue light would undergo total internal reflection.

Q.

Can reflection result in plane polarised light if the light is incident on the interface from the side with higher refractive index?

Q.

The angle between an incident ray and the normal to the surface of the mirror is ${40}^o$.

1. What is the angle of incidence?
2. What is the angle of reflection?

Q. PQR is a right angled prism with other angles as ${60}^{\circ }$ and ${30}^{\circ }$. Refractive index of prism is 1.5. PQ has a thin layer of liquid. Light falls normally on the face PR. For total internal reflection, maximum refractive index of liquid is

1. 1.3
2. 1.2
3. 1.4
4. 1.6

Q. If $i={90}^{\circ },$ find minimum value of angle of prism $A$ in degrees for which emergence is not possible:

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

Q. A light ray goes from a medium of refractive index$\sqrt{2}$ to a medium of refractive index 1. The minimum angle of incidence for TIR to happen is .

1. ${30}^{\circ }$
2. ${45}^{\circ }$
3. ${60}^{\circ }$
4. ${90}^{\circ }$