Tag: physics

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Multiple choice physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

Two pont white are 1 mm apart on a black paper. They are viewed by eye of pupil diameter 3 mm. Approximately, what is the maximum distance at which these dots can be resolved by the eye ? [Take wavelength of light = 500 nm]

  1. 5 m

  2. 1 m

  3. 6 m

  4. 3 m
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Using Rayleigh's criterion, the angular resolution is theta = 1.22 * lambda / D. With lambda = 500 nm and D = 3 mm, theta = 1.22 * 500e-9 / 0.003 = 2.03e-4 radians. For a separation of 1 mm (0.001 m), the distance L = 0.001 / 2.03e-4, which is approximately 4.92 meters, rounding to 5 meters.

Multiple choice physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

If you read the words of your book, the reflection is

  1. specular reflection

  2. diffused reflection

  3. may be specular may be diffused

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Reading words from a book involves light reflecting off the surface in many directions so that it can be seen from various angles. This scattering of light is known as diffused reflection.

Multiple choice physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

Image formation takes place by

  1. specular reflection

  2. diffused reflection

  3. Both (a) and (b)

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Image formation, such as in a mirror or through a lens, relies on the regular, predictable reflection or refraction of light rays. This is characteristic of specular reflection.

Multiple choice physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

The distance of the eye-lens from the retina is $x$. For a normal eye, the maximum focal length of the eye-lens

  1. $= x$
  2. $< x$
  3. $> x$
  4. $= 2x$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Focal length of normal eye lens is equal to the distance between eye-lens and retina i.e, $x$  so that all rays converges on retina after passing through  eye-lens

Multiple choice physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

The persistence of vision for normal human eye is :

  1. $1/{ 10 }^{ th }$ of a second
  2. $1/{ 16 }^{ th }$ of second
  3. $1/{ 6 }^{ th }$ of a second

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The persistence of vision is the phenomenon where an image remains on the retina for a fraction of a second after the stimulus is removed, typically cited as 1/16th of a second.

Multiple choice physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

Refraction of light in the eye occurs at ............

  1. The lens only

  2. Cornea only

  3. both cornea and lens

  4. The Pupil
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Refraction of light in the human eye occurs primarily at the cornea, which provides most of the eye's refractive power, and is further adjusted by the crystalline lens.

Multiple choice physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

A series of fast moving still pictures can create an illusion of movement because.

  1. the eye can focus on very rapidly changing pictures

  2. eye is quicker than the brain

  3. the eye can separate two images only when the interval of separation between them is more than one-tenth of a second

  4. the optical cortex can see through the rapidly moving images
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Human eye cannot differentiate two images when the interval of separation between them is less than one-tenth of a second

Multiple choice physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

Which part of human eye controls the amount of light entering the eye?

  1. Cornea

  2. Retina

  3. Pupil

  4. Iris
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Correct answer is (D)

Iris is the ring of pigmented tissue surrounding the pupil that varies in color from person to person, it contract and dilates to control the amount of light entering the eye through the pupil. The pupil is the opening in the center of the iris where light enters the eye. 

Multiple choice physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

The presistence of the eye is only for:

  1. 1/100th of a second

  2. 1/120th of a second

  3. 1/16th of a second

  4. 1/200th of a second
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

According to Persistence of Vision theory, the human eye has the illusion of an after image still persisting. It is when our eye has the ability to persist for 1/16 of a second after the image has removed. It is used in animation to show fluent movement, normally after every two frames one picture would be shown, so for every 24 frames 12 pictures will be shown. This gives us the illusion of movement and the afterimage persists on our retina. 

Multiple choice physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

Which of the following is Not an advantage of having two eyes?

  1. It gives a wider field view.

  2. The ability to detect faint objects is enhanced with two detectors instead of one.

  3. It gives the ability to interpret the closeness of an object.

  4. It gives the eye higher protection from dust and pollution.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

There are several advantages of our having two eyes instead of one.
(i) It gives a wider field view because human being has a horizontal field view of about 150∘150∘ with one eye and of about 180∘180∘with two eyes.
(ii) The ability to detect faint objects is enhanced with two detectors instead of one.
(iii) With one eye, the world looks flat, i.e., two dimensional-only. With two eyes, the view is three dimensional.
As our two eyes are separated by a few centimeters each eye observes a slightly different image. Our brain combines the two views into one and we get to know how close or far away the things observed are.