Advertisements
Advertisements
प्रश्न
Choose the correct option.
There are different fish, monkeys, and water of the habitable planet of the star Proxima b. A fish swimming underwater feels that there is a monkey at 2.5 m on the top of a tree. The same monkey feels that the fish is 1.6 m below the water surface. Interestingly, height of the tree and the depth at which the fish is swimming are exactly same. Refractive index of that water must be
पर्याय
`6/5`
`5/4`
`4/3`
`7/5`
उत्तर
`5/4`
Explanation:
As, height of the tree = depth at which fish swimming, Real depth, or height in both conditions is same, (say) x.
∴ For monkey, as apparent depth = 1.6 m,
`"n"_"water"/"n"_"air"="Real depth"/"Apparent depth"="x"/1.6`
For fish, as apparent height = 2.5 m,
`"n"_"air"/"n"_"water"="Real height"/"Apparent height"="x"/2.5`
∴ `"x"/1.6xx"x"/2.5` = 1
∴ x2 = 4 ⇒ x = 2
∴ `"n"_"water"/"n"_"air"="x"/1.6=2/1.6=5/4`
APPEARS IN
संबंधित प्रश्न
Double-convex lenses are to be manufactured from a glass of refractive index 1.55, with both faces of the same radius of curvature. What is the radius of curvature required if the focal length is to be 20 cm?
A small pin fixed on a table top is viewed from above from a distance of 50 cm. By what distance would the pin appear to be raised if it is viewed from the same point through a 15 cm thick glass slab held parallel to the table? Refractive index of glass = 1.5. Does the answer depend on the location of the slab?
A diver under water, looks obliquely at a fisherman standing on the bank of a lake. Would the fisherman look taller or shorter to the diver than what he actually is?
Monochromatic light of wavelength 589 nm is incident from air on a water surface. If µ for water is 1.33, find the wavelength, frequency and speed of the refracted light.
A fish which is at a depth of l2 em .in water `(mu = 4/3)` is viewed by an observer on the bank of a lake. Its apparent depth as observed: by the observer is:
a) 3 cm
b) 9 cm
c) 12 cm
d) 16 cm
A narrow beam of light passes through a slab obliquely and is then received by an eye following figure. The index of refraction of the material in the slab fluctuates slowly with time. How will it appear to the eye? The twinkling of stars has a similar explanation.
A laser light is focussed by a converging lens. Will there be a significant chromatic aberration?
A narrow beam of white light goes through a slab having parallel faces.
(a) The light never splits in different colours
(b) The emergent beam is white
(c) The light inside the slab is split into different colours
(d) The light inside the slab is white
If the light moving in a straight line bends by a small but fixed angle, it may be a case of
(a) reflection
(b) refraction
(c) diffraction
(d) dispersion.
A pole of length 1.00 m stands half dipped in a swimming pool with water level 50.0 cm higher than the bed. The refractive index of water is 1.33 and sunlight is coming at an angle of 45° with the vertical. Find the length of the shadow of the pole on the bed.
A vessel contains water up to a height of 20 cm and above it an oil up to another 20 cm. The refractive indices of the water and the oil are 1.33 and 1.30 respectively. Find the apparent depth of the vessel when viewed from above.
A converging beam of light traveling in air converges at a point P as shown in the figure. When a glass sphere of refractive index 1⋅5 is introduced in between the path of the beam, calculate the new position of, the image. Also, draw the ray diagram for the image formed.
Answer the following question.
Define absolute refractive index and relative refractive index. Explain in brief with an illustration for each.
What is angle of deviation due to refraction?
What is relative refractive index?
Why do stars twinkle?
Write a short note on the prisms making use of total internal reflection.
How does an endoscope work?
Obtain the equation for radius of illumination (or) Snell’s window.
Obtain the equation for lateral displacement of light passing through a glass slab.
A light travels through water in the beaker. The height of water column is 'h'. Refractive index of water is 'μw'. If c is velocity of light in air, the time taken by light to travel through water will ______.
A ray of light passes through equilateral prism such that the angle of incidence is equal to angle of emergence and each of these angles is equal to `(3/4)^"th"` the angle of prism. The angle of deviation is ______.
When a ray of light is incident normally on one refracting surface of an equilateral prism of refractive index 1.5, the emerging ray ______.
`[sin^-1(1/1.5)=41.8^circ]`
Light travels from an optically denser medium 'A' into the optically rarer medium 'B' with speeds 1.8 × 108 m/s and 2.7 × 108 m/s respectively. Then critical angle between them is ______.
(µ1 and µ2 are the refractive indices of media A and B respectively.)
Light travels in two media A and B with speeds 1.8 × 108 ms−1 and 2.4 × 108 ms−1 respectively. Then the critical angle between them is:
A ray of unpolarised light is incident on the surface of glass plate of µ = 1.54 at polarising angle, then angle of refraction is
A circular disc of radius ‘R’ is placed co-axially and horizontally inside an opaque hemispherical bowl of radius ‘a’ (Figure). The far edge of the disc is just visible when viewed from the edge of the bowl. The bowl is filled with transparent liquid of refractive index µ and the near edge of the disc becomes just visible. How far below the top of the bowl is the disc placed?
