Physics

Optical Instruments and Human Eye

428 Questions

Optical instruments and the human eye explore how lenses and mirrors are used to magnify and resolve images. Key topics include the magnifying power of astronomical telescopes, compound microscope configurations, and hyperfocal distance calculations. These physics concepts are vital for general science competitive exams.

Telescope magnifying powerCompound microscope lensesHyperfocal distance calculationHuman eye resolutionSpherical mirror magnification

Optical Instruments and Human Eye Questions

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

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

What kind of lens is there in our eyes? 

  1. concave

  2. convex

  3. Plano-concave

  4. Plano-convex
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Answer is B.
Our eye lenses are convex lenses with variable focal lengths. The focal length of the eye lens is controlled by muscles according to the distance of the object from us that we are trying to see. The lens is flexible and when it is acted on by the ciliary muscle around it, the lens can be "flattened" to change the focus, or, when the muscle is relaxed, the lens can be assumed as having a more spherical shape. This is the principle of the eye to focus on objects nearer or farther away.

Multiple choice biology human brain and sense organs introduction to sense organs eyes and their function the structure and function of the eye

The human eye is sensitive only to light having wave length ranging from 

  1. 80 to 280 nanometres

  2. 380 to 760 nanometres

  3. 780 to 870 nanometres

  4. 880 to 980 nanometres
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The human eye is sensitive to violet (400 nm) to red (700 nm ) light only that can generate photometric effect i.e. visual sensation on an eye. So, the correct answer is option B.

Multiple choice bio-chemistry unit of living - cell eukaryotic cell kinds of cell introduction to eukaryotic cell
Read the passage and answer the following question.

A student, using a compound microscope, with a $10 \times $ ocular lens and a $4 \times $ objective lens measured his field of view with a plastic ruler and found it to be $4 mm$. He then placed some of his cheek cells on a slide, found them using the $4 \times$ objective lens and switched to the $40 \times$ objective lens. He counted twelve cells, side by side, that stretched from one side of the field of view to the other. 

The diameter of a cheek cell is
  1. $0.033 mm$
  2. $0.132 mm$
  3. $0.0132 mm$
  4. $0.0033 mm$
  5. $1.32 mm$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Ocular lens $ = 10x $
Objective lens $ = 4x $
Field of view $ = 4\,mm $
When he placed cheek cell using $ 4x $ objective lens and the $ 40x $ objective lens.
$ \Rightarrow $ Diameters of cheek cell is $ 0.033\,mm $ 
Multiple choice physics wave optics difference between interference and diffraction explaining wave phenomena diffraction

For what distance is ray optics a good approximation when the aperture is 4 mm wide and the wavelength is 500 nm? 

  1. 22 m

  2. 32 m

  3. 42 m

  4. 52 m
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Given:
 Aperture Width $a =4 $mm
Fresnel distance, $Z _F \, = \, \dfrac{a^2}{\lambda} \, = \, \dfrac{(4 \, \times \, 10^{-3})^2}{500 \, \times \, 10^{-9}}$
$\therefore \, z _p \, = \, 32 \, m$
Multiple choice

What are the trade-offs of using the 400x (power) on the microscope?

  1. You can only see a bigger section of the slide

  2. You can't see anything

  3. You can only see a smaller section of the slide

  4. You can see more
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

As magnification increases, the field of view decreases, meaning you see a smaller portion of the slide but in greater detail.

Multiple choice

What is a microscope used for...

  1. to see things that are too small to see with the human eye

  2. to see things that are too big to see with the human eye

  3. to see things in space

  4. to drive Ms. Borchardt crazy by dinging the stage clips
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A microscope is an optical instrument used to magnify objects that are too small to be seen by the naked eye.

Multiple choice botany cell structure and micro-organisms cell theory microscope cell and its discovery

Magnification power of a light compound microscope depends on

  1. Power of eye piece lens

  2. Power of an occular lens

  3. Both A and B

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The power of magnification of a microscope is the product of the powers of the occular (eyepiece) and the objective lens. The maximum normal magnifications of the occular and the objective are 10x and 100x respectively, giving a final magnification of 1,000x.

Multiple choice botany cell and cellular organization cell theory microscope cell and its discovery

9X was the maximum magnification of .......... microscope.

  1. First

  2. Second

  3. Advanced

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

A- A microscope helps in magnifying small objects. Zacharias Jansen and his father Hans created the first microscope in 1595. This microscope was made up of a long brass tube with two lenses. 9X was the maximum magnification of this microscope. Magnification helps in viewing an object by making it larger.

Multiple choice botany cell and cellular organization cell theory microscope cell and its discovery

An optical instrument used to observe small organism is called as_____________.

  1. Microscope

  2. Telescope

  3. Magnifying lens

  4. Both A and B
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A- Microscope is a device which is used to view objects that are very small for the naked eye. Light microscopes also known as optical microscopes are the most common type of microscopes. Optical microscopes utilize light and lenses to magnify images.