Ray Optics · Physics · COMEDK
MCQ (Single Correct Answer)
The critical angle for a typical glass air interface is $42^{\circ}$. If a ray of light falls normally on one of the faces of the prism of angle $45^{\circ}$. The emergent ray will:
The distance between the objective and eye piece of astronomical telescope in normal adjustment is 27 cm and its magnifying power is 8 . What is the focal length of the eye piece?
The ratio of the angle of deviation produced by a thin prism, when it is placed in air to the angle of deviation produced when it is immersed in water of refractive index $\frac{4}{3}$ is:
An object placed 40 cm in front of a thin convex lens is moved to 60 cm from the lens. If the focal length of the lens is 30 cm the ratio of magnification of the image at the initial position to the final position is:
An object is placed 25 cm in front of a fully silvered concave mirror of focal length 15 cm . A plane mirror is placed 35 cm behind the concave mirror on the side opposite to the object. The final image after reflection first from the concave mirror and then from the plane mirror is formed at:
A glass slab of 16 cm thickness has its bottom surface silvered. An air bubble is located inside the glass slab at a distance of 8 cm from the top surface. The refractive index of glass is 1.6 . Which of the following correctly represents the number of images seen by an observer looking vertically downwards from air onto the top surface?
A. Only one image is seen at a depth of 5 cm
B. Multiple images are formed due to multiple reflections and refractions
C. Only one image is seen at a depth of 16 cm
D. Two images are seen at depths 5 cm and 15 cm
An object is placed at an unknown distance from a convex objective lens of focal length 5 cm . The objective lens forms a real image which acts as an object for a convex eyepiece of focal length 6.25 cm . The distance between the objective and eyepiece is 20 cm . The microscope is adjusted so that the final image is formed at the least distance of distinct vision $(25 \mathrm{~cm})$. Which of the following is correct?
A. Object distance $=7.5 \mathrm{~cm}$; Total magnification $=10$
B. Object distance = 10 cm ; Total magnification = 20
C. Object distance $=5 \mathrm{~cm}$; Total magnification $=20$
D. Object distance = 2.5 cm ; Total magnification = 10
If a clear liquid has a refractive index of 1.45 and a transparent solid has a refractive index of 2.9 , then for total internal reflection to occur at the interface between the two media; which of the following is correct?
A. The ray must travel from transparent solid to liquid at an angle of $15^{\circ}$
B. The ray must travel from liquid to transparent solid at an angle of $45^{\circ}$
C. The ray must travel from transparent solid to liquid at an angle of $30^{\circ}$
D. The ray must travel from liquid to transparent solid at an angle of $60^{\circ}$
A telescope has an objective of focal length $$60 \mathrm{~cm}$$ and eyepiece of focal length $$5 \mathrm{~cm}$$. The telescope is focussed for least distance of distinct vision $$300 \mathrm{~cm}$$ away from the object. The magnification produced by the telescope at least distance of distinct vision is
Figure below shows a lens of refractive index, $$\mu=1.4$$. $$C_1$$ and $$C_2$$ are the centres of curvature of the two faces of the lens of radii of curvature $$4 \mathrm{~cm}$$ and $$8 \mathrm{~cm}$$ respectively.
The lens behaves as a
When a biconvex lens of glass of refractive index 1.5 is dipped in a liquid, it acts like a plane sheet of paper. This means the refractive index of the liquid is
A hollow prism is filled with water and placed in air. It will deviate the incident rays
An object is placed at a distance of $$12 \mathrm{~cm}$$ from a convex lens on its principal axis and a virtual image of certain size is formed. If the object is moved $$4 \mathrm{~cm}$$ away from the lens, a real image of the same size as that of the virtual image is formed. The focal length of the lens in $$\mathrm{cm}$$ is
To a fish under water, viewing obliquely, a fisherman standing on the bank of a lake looks
In a container of height $$21 \mathrm{~cm}$$, certain transparent liquid is taken to a height of $$12 \mathrm{~cm}$$. When seen from above, it appears half filled. The refractive index of the liquid is
Light enters at an angle of incidence in a transparent rod of refractive index '$$n$$'. The least value of '$$n$$' for which the light once entered into it will not leave it through its lateral face whatsoever be the value of the angle of incidence is
In the normal adjustment of an astronomical telescope, the objective and eyepiece are $$32 \mathrm{~cm}$$ apart. If the magnifying power of the telescope is 7, find the focal lengths of the objective and eyepiece.
When a particular wave length of light is used the focal length of a convex mirror is found to be $$10 \mathrm{~cm}$$. If the wave length of the incident light is doubled keeping the area of the mirror constant, the focal length of the mirror will be:
For a $$30^{\circ}$$ prism when a ray of light is incident at an angle $$60^{\circ}$$ on one of its faces, the emergent ray passes normal to the other surface. Then the refractive index of the prism is:
A ray of light travelling through a medium of refractive index $$\frac{5}{4}$$ is incident on a glass of refractive index $$\frac{3}{2}$$. Find the angle of refraction in the glass, if the angle of incidence at the given medium - glass interface is $$30^{\circ}$$.
An air bubble in water $$\left(\mu=\frac{4}{3}\right)$$ is shown in figure. The apparent depth of the image of the bubble in plane mirror viewed by observer is.
A fish in water (refractive index $$n$$ ) looks at a bird vertically above in the air. If $$y$$ is the height of the bird and $$x$$ is the depth of the fish from the surface, then the distance of the bird as estimated by the fish is
The critical angle of a medium having the refractive index $$\sqrt2$$ is :
When angle of incidence on one face of the equilateral glass prism is $$3 / 4^{\text {th }}$$ of the angle of prism, the ray of light undergoes minimum deviation. If the velocity of light in vacuum is '$$c$$' then the velocity of light in the glass is :
A person has a normal near point $$25 \mathrm{~cm}$$. What is the magnifying power of the simple microscope he used, if the focal length of the convex lens used is $$10 \mathrm{~cm}$$ and the final image is formed at the least distance of distinct vision?
A lens of power $$+1 \mathrm{D}$$ is made in contact with another lens of power $$-2 \mathrm{D}$$ the combination will then act as a:
What will be change in wave length, if a light of wave length $$600 \mathrm{~nm}$$ travels from air enters a medium of refractive index 1.5 and continues its journey through that medium?
A point object is placed on the optic axis of a convex lens of focal length $$f$$ at a distance of $$2f$$ to the left of it. The diameter of the lens is $$d$$. An eye is placed at a distance of $$3f$$ to the right of the lens and a distance $$h$$ below the optic axis. The maximum value of $$h$$ to see the image is
A plane glass mirror of thickness 3 cm of material of $$\mu=\frac{3}{2}$$ is silvered on the black surface. When a point object is placed 9 cm from the front surface of the mirror, then the position of the brightest image from the front surface is
Two converging lenses of focal length 20 cm and 40 cm are placed in contact. The effective power of the combination is
The magnifying power of a telescope is 9. When it is adjusted for parallel rays, the distance between the objective and eyepiece is 20 cm. The focal length of lenses are
A convex lens is made of 3 layers of glass of 3 different materials as in the figure.
A point object is placed on its axis. The number of images of the object are
A ray of light suffers minimum deviation in equilateral prism P. Additional prisms Q and R of identical shape and of same material as that of P are now combined as shown in figure. The ray will now suffer
