Refraction and Laws of Refraction

Q. When a ray of light enters a denser medium from a rarer medium:

1. It bends towards the normal
2. It bends away from the normal
3. It does not bend
4. It always gets reflected

Q. when a light ray enters a refracting medium , it is found that magnitude of the angle of refraction is equal to half the angle of reflection.if n is the refractive index of the medium , find the angle of incidence.why is the refractive index of medium 1 taken as 1 here?

Q.

The angle of incidence is equal to the angle of reflection.

1. Always

2. Sometimes

3. Under special condition

4. Never

Q. What are the two laws of refraction of light?

Q.

Which of the following statements is true?

1. A convex lens has 4 dioptre power having a focal length $0.25\mathrm{m}$.

2. A convex lens has $–4$ dioptre power having a focal length $0.25\mathrm{m}$.

3. A concave lens has $4$ dioptre power having a focal length $0.25\mathrm{m}$

4. A concave lens has $–4$ dioptre power having a focal length $0.25\mathrm{m}$

Q. A ray of light falls on a glass slab of refractive index of root3. If the reflected and refracted rays are mutually ||lar, find the angle of incidence.

Q. The refractive index of air, water, diamond and crown glass is 1.0003, 1.33, 2.42 and 1.52 respectively. In which medium the speed of light would be the slowest?

1. Air
2. Water
3. Diamond
4. Crown glass

Q.

A rectangular glass slab ABCD, of refractive index n₁, is immersed in water of refractive index n₂ (n₁>n₂). A ray of light in incident at the surface AB of the slab as shown. The maximum value of the angle of incidence a_max, such that the ray comes out only from the other surface CD is given by

1. 
   

2. 
   

3. 
   

4. 
   

Q. The phenomenon of light changing its direction when it obliquely passes from one medium to another, is called .

1. reflection
2. refraction
3. magnification
4. diffraction

Q.

A shopkeeper wanted to fix a mirror which will give a maximum view of his shop. What type of mirror should he use? Give reason.

Q. For the same angle of incidence of 45° the refraction angle in 3 transparent media A, B and C are 25°, 30° and 45° respectively. In which medium is the speed of light minimum and in which medium maximum?

Q. A student very cautiously traces the path of a ray through a glass slab for different values of the angle of incidence (∠i). He then measures the corresponding values of the angle of refraction (∠r) and the angle of emergence (∠e) for every value of the angle of incidence. On analyzing the measurements of these angles, his conclusion would be:

1. ∠i >∠r > ∠e
2. ∠i = ∠e > ∠r
3. ∠i = ∠e < ∠r
4. ∠i < ∠r < ∠e

Q. What is the unit of the refractive index?

1. Metre
2. Kilogram
3. Seconds
4. No unit

Q.

A car moves with a speed of $40km/hr$ for $15minutes$ and then with a speed of $60km/hr$ for the next $15minutes$. The total distance covered by the car is:

1. $100km$

2. $25km$

3. $15km$

4. $10km$

Q. The incident ray, the refracted ray and the normal at the point of incidence all lie _____.

1. in different planes
2. in mutually perpendicular planes
3. in the same plane
4. at an angle of ${45}^{\circ }$ to each other

Q. In a rectangular glass slab, a light ray is incident obliquely on the interface. i, r, and e are the angles of incidence, refraction, and emergence, respectively. Select the correct statement.

1. ∠i is more than ∠r but nearly equal to ∠e.
2. ∠i is less than ∠r but nearly equal to ∠e.
3. ∠i is more than ∠e but nearly equal to ∠r.
4. ∠i is less than ∠e but nearly equal to ∠r.

Q.

What is the lateral shift surface in the light ray refracted by a rectangular glad slab? On what factors does it depend ?

Q. A light ray entered a rectangular glass slab. if $i$ be the angle of incidence and $e$ be the angle of emergence, then:

1. $e=i$
2. $e>i$
3. $e<i$
4. $i\ne e$

Q. Question 29
Draw a ray diagram showing the path of rays of light when it enters with oblique incidence (i) from air into water; (ii) from water into air.

Q.

Critical Angle is defined as

1. angle of incidence in rarer medium for which the angle of refraction in denser medium is 90°

2. angle of incidence in denser medium for which the angle of refraction in rarer medium is more than 90°

3. angle of incidence in denser medium for which the angle of refraction in rarer medium is 90°

4. angle of incidence in denser medium for which the angle of refraction in rarer medium less than 90°

Q. when a Ray of light is incident at an angle 60 degree to a medium of refractive index n, it is observed that the angle of refraction is half the angle of incidence the value of n is

Q. Alex is doing an experiment with a white laser light inside a dark lab.
(i) Explain the phenomenon of dispersion that he will observe when passing the white light through a glass prism, using suitable ray diagram.

Q. The refractive index of glass is 1.520 for red light and 1.525 for blue light. Let $D_1$ and $D_2$ be angles of minimum deviation for red and blue light respectively in a prism of this glass. Then :

1. $D_1>D_2$
2. $D_1$ can be less than or greater than $D_2$ depending upon the angle of prism
3. $D_1<D_2$
4. $D_1=D_2$

Q.

The refractive index of air w.r.t. glass is expressed as _gμ_a = ^sini/_sinr

If the angle r = 90^o, what is the corresponding angle ‘i’ called ?

1. Angle of emergence

2. Angle of deviation

3. Critical Angle

4. Angle of refraction

5. Angle of reversibility of Light

Q. A light ray passes from glass with R.I root3 into air. Find the angle if incidence for which angles of refraction will be double of angle of incidence .

Q. In the case of refraction of light in a rectangular glass slab, if $\text{i}$ is the angle of incidence and $\text{e}$ is the angle of emergence, then:

1. $\text{e}=\text{i}$
2. $\text{e}<\text{i}$
3. $\text{e}>\text{i}$
4. $\text{e}$ and $\text{i}$ are unrelated

Q. When a white light ray falls on a prism, the ray at its first surface suffers.

Q. A ray of light is incident at 60°, on glass-air interface. Then the light ray will-

Q. A ray of white light passes from medium 1 to medium 2.
Which of the following quantities of the refracted ray will differ from that of the incident ray?

1. Speed
2. Intensity
3. Frequency
4. Wavelength

Q. Explain Newton's experiment with suitable diagram.
$\left[5\text{marks}\right]$