Ray Optics and Optical Test

Result

Ray Optics and Optical Test - 57

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Weekly Quiz Competition

Question 1
1 / -0

Four similar prism of same material having same angle of prism are arranged. Which of the following arrangements given no net angular deviation ?

A

B

C

D
Solution
Question 2
1 / -0

The limit of resolution of microscope, if the numerical aperture of microscope is $$0.12$$, and the wavelength of light used is $$600\ nm$$, is:

A
$$0.3\mu m$$

B
$$1.2\mu m$$

C
$$2.3\mu m$$

D
$$3\mu m$$

Solution
Question 3
1 / -0

A thin prism of angle $$7^o$$ made of glass of refractive index $$1.5$$ is combined with another prism made of glass of $$\mu =1.75$$ to produce dispersion without deviation. The angle of second prism is :

A
$$7^o$$

B
$$4.67^o$$

C
$$9^o$$

D
$$5^o$$

Solution
Question 4
1 / -0

The rising and setting of sun appear red because of :

A
refraction

B
reflection

C
defraction

D
scattering

Solution

The reddish appearance of the sun at sunrise or sunset is due to scattering of light by the molecules of air and other fine particles in the atmosphere.

Hence the option D is the right answer
Question 5
1 / -0

Refracting angle is the prism $$ \phi $$ (see figure) is $$ 30^{\circ} $$. The angle of incidence of the beam on the face of the prism $$ \alpha = 37^{\circ} $$ . Determine the angle of deviation $$ \delta $$ (in degree) of ray the from the original direction after passing through the prism. The refractive index of the material of the prism $$ n = 1.2.$$ Round off the answer to the nearest integer :

A
$$ 30^{\circ} $$.

B
$$ 37^{\circ} $$

C
$$ 7^{\circ} $$

D
$$ 0^{\circ} $$

Solution
Question 6
1 / -0

Figure shows converging rays on a glass slab placed in air . O is point of intersection of incident rays $$ I_1 $$ and $$ I_2 $$ are image formed after refraction at $$ S_1 $$ and $$ S_2 $$ surface respectively . Mark the correct options(s) :

A
For refraction at $$ S_2, I_1 $$ is real object and $$ I_2 $$ is real image

B
For refraction at $$ S_1, O $$ is real object and $$ I_1 $$ is its real image

C
For refraction at surface $$ S_1, O $$ is virtual object and $$ I_1 $$ is real image

D
For refraction at surface $$ S_2 , I_1 $$ is virtual object and $$ I_2 $$ is real image

Solution

For S 1 the real image is I 1 and Virtual Image is O
For S 2 the real image is I 2 and Virtual image is I 1
Question 7
1 / -0

A light ray is normally incident on a right angled prism of refractive index $$ 2.1$$ as shown. How many total internal reflections can the ray undergo inside the prism before coming out of the prism. Consider possible cases :

A
$$ 1 $$

B
$$ 2 $$

C
$$ 3 $$

D
$$ 4 $$

Solution

Condition of Total Internal Reflection-
1. Light travel slower in first medium than in second medium.
2. Light will move through the medium of higher refractive index to lower refractive index.
3.Critical angle (C) is defined when the angle of refraction is 90 degree to the normal
4.Total internal reflection occur when angle of incidence is larger then critical.
Apply snell`s law at incident surface ,the light will bend towards the normal and strike the next surface , there is chance of Total internal reflection at this surface and also if it will not undergo total internal reflection at this surface then there might be chance of total internal reflection at the next surface.
Question 8
1 / -0

From the base of a hollow cone of height $$ h $$ with a small angle at the top, a small ring was cut off and placed in front of a parallel beam of light (the figure is exaggerated for clarity). At what distance x will rays of light reflected from it intersect the axis of the cone.

A
$$ h $$

B
$$ \dfrac{h}{2} $$

C
$$ \dfrac{h}{\sqrt{2}} $$

D
$$ \sqrt{\dfrac{2}{3}} h $$
Question 9
1 / -0

Consider a system of two thin lenses as shown in figure. An object of height $$ 1\, cm $$ is placed at $$ 40\,cm $$ from convex lens. Mark the correct option related to final image formed by the two-lens-system :

A
Final image is formed at $$ 32\,cm $$ on right of concave lens and is $$ \dfrac{1}{2.2} \,cm $$ in size .

B
Final image is formed at $$ 32\,cm $$ on left side of convex lens and is $$ 1\,cm $$ in size .

C
Final image is formed at $$ 14.5\,cm $$ on the left side of of concave lens and is $$ \dfrac{1}{2.2} \,cm $$ in size .

D
None of the above

Solution
Question 10
1 / -0

A concave mirror has a focal length of 25 cm. At which of the following distance should a person hold his face from this concave mirror so that it may act as a shaving mirror ?
Give reason for your choice.

A
45 cm

B
20 cm

C
25 cm

D
30 cm

Solution

20 cm, because if the object is placed between the pole and focus of the concave mirror only then the image formed is erect and magnified.