Which liquid fill in the space between eye lens and retina?
Which part of the eye can be donated after death?
Name the phenomena responsible for rainbow formation.
Where is the image formed in an eye suffering from near sightedness?
Where is the image formed in an eye suffering from long sightedness?
What is the twinkling of stars due to?
When sunlight enters a dark smoke filled room, its path becomes visible. Name the phenomenon responsible for this.
Which phenomenon is responsible for increasing the apparent length of the day by 4 min?
What is the function of the liquid filled in the space between eye lens and retina?
Which part of humans eye is also known as "white of the eye?"
Variables focal length of eye lens is responsible for which property of eye?
Where do we use the property of persistence of vision?
What is the nature of an image formed on the retina of the eye?
What happens to the lens and the cilliary muscles when you are looking at nearby objects?
What is the relation between intensity of scattered light and its amplitude?
Why do we observe random wavering or flicking of the objects near a fire or on a very hot day?
A man is wearing glassses of focal length +1m, what can be defect in the eye?
Why are danger signal lights red in colour?
What would have been the colour of the sky, if the Earth had no atmosphere?
where do we see
(i) Concave lens and
(ii) Convex lens in a bifocal spectacle?
Why are we not able ot see the things clearly when we come out of a dark room?
What happens to the pupil of the eye when the light is
(i) very bright and
(ii) very dim?
Name the part of an eye which is equivalent to
(i) diaphragm and
(ii) photographic plate, in a camera.
A piece of cloth appears red in sunlight. How will it appear when held in the blue portion of a spectrum?
Bees are able to see ultraviolet light. Comment.
How does coloured television sets and computer monitors produce the entire range of colours?
In a human eye ,name the following parts .
(i) A thin membrane which allows light to enter into the eye?
(ii) The muscles which help in changing the focal length of the eye lens?
Name the four parts labelled as 1, 2, 3, and 4 in the given figure.
What are the two types of light sensitive cells on retina of an eye? Which of these cells respond to colour and intensity of light?
When sunlight passes throught the canopy of a dense forest, the light is scattered. Explain.
What is the nature of the image formed on the retina? What kind of lens is present in our eye?
Name the screen on which an image is formed in the eye. What is the range of vision of a normal human eye?
State the phenomenon involved in the formation of a rainbow in the sky. Arrange these phenomenon in proper sequence.
Name the phenomenon responsible for
(i) advance sunrise
(ii) Colour of water in deep sea
(iii) Twinkling of stars
(iv) reddish appearance of the Sun at the time of sunrise and sunset
Why it is difficult to drive on a foggy day?
What is dispersion? What happens when light is passed through a glass prism?
What is the colour of an emergent light when white light is passed through a colloidal solution of sulphur? Explain.
Explain the role of pupil and iris.
Calculate maximum power of accommodation of a person having normal vision.
A person wants to read a book placed at 20 cm, whereas near point of his eye is 30 cm. Calculate the power of hte lens required.
A myopic person can see things clearly only when they lie between 10 cm and 100 cm from the eye. Which lens will enable him to see the Moon clearly ?
When sometimes rings are observed round the Moon or the Sun?
When one enters a less lighted room from a place of intense light, he is not able to see anything for sometime, but after sometime the things become somewhat visible. Explain how this happens?
Why does it take sometime to see objects in a cinema hall when we just enter the hall from bright sunlight? Explain in brief.
Why does it take sometime to see the objects in a dim light room when we enter the room from bright sunlight outside?
How can change of size of eyeball be one of the reason for
(i) myopic and
(ii) hypermetropia eye?
Compare the size of eyeball with that of a normal eye in each case. How does this change of size affect the position of image in each case?
When a beam of white light is passed through a triangle glass prism, it gets dispersed into its seven colour components. Why do we get these colours? In the given figure, the colours X and Y represent the extreme components of the spectrum. Identify X and Y.
A beam of white light falling on a glass prism gets split up into seven colours market 1 to 7 as shown in the diagram.
(i) The colour at position marked 3 and 5 are similar to the colour of the sky and the colour of gold metal, respectively. Is the above statement made by the student correct or incorrect justify?
(ii) Which of the above shown position corresponds approximately to the colour of (a) brinjal, (b) danger signal, (c) neel which is applied to clothes, (d) orange.
Why do we observe difference in colours of the Sun during sunrise, sunset and noon?
During sunrise and sunset, sky appears red while during the day it appears blue. Explain this natural phenomenon.
Why does a student suffering from far sightedness prefer to remove his spectacles while looking at distant objects?
A man can read the number of a distant bus clearly but he finds difficulty in reading a book. From which defect of the eye he is suffering from? What type of spectacles lens should be used to correct the defect?
What change is made in the eye to enable it to focus an object situated at different distances?
Explain, the role or importance of ciliary muscle in eye accomodation.
Explain, why the Sun overhead at noon, appears white?
Under very dim light, we are able to see all the objects but cannot distinguish between their colours. Explain.
A person can see object up to distance x, but desires to see an object clearly which is lying at a distance y from him. What should be the focal length of suitable lens?
The sun near the horizon appears flattened at the sunset and sunrise. Explain, why?
Why a rectangular glass slab does not cause dispersion of white light like prism?
A camera in many ways is similar to the human eye, still there are some basic differences in image formation between the two. Explain.
Name the part of the eye that
(i) control the amount of light entering the eye.
(ii) determine the colours of a person's eye.
(iii) focus objects at different distances on the retina.
Sun is visible 2 min before actual sunrise and 2 min after sunset. Given reason.
Explain, how scattering of light depends upon particle size?
Why do the objects appear to flicker when seen through a turbulent stream of hot air rising above a fire or a radiator?
List two main causes of a person developing near sightedness. Show with the help of a ray diagram how this defect can be corrected.
State one main function each of iris, pupil, and cornea.
How do we see objects erect when the eye forms a real, inverted image of them on its retina?
Draw a labelled diagram of human eye. what is the significance of the blind spot and yellow spot?
(i) Why does power to see clearly near objects as well as far off objects diminish with age? Name the defects that are likely to arise in eye in such a condition.
(ii) The far poin of a myopic eye is 60 cm. Find the focal length of the lens used to correct it.
When and where do we see a rainbow? How is a window formed? Draw a labelled diagram to illustrate the formation of a rainbow.
Describre the formation of rainbow in the sky with the help of a diagram.
A doctor has prescribed a corrective lens of power - 1.2 D to a person suffering from defect of vision.
(i) Identify the defect from which he is suffering.
(ii) Find the focal length of the lens.
(iii) Is the prescribed lens diverging or converging? Show the nature of this lens with the help of a ray diagram.
Why do different colours get separated when a white light passes through a prism? How can we recombine the components of white light after a prism has separated them? Explain with the help of figure.
(i) Ravi kept a book at a distance of 10 cm from the eyes of his friend Hari. Hari is not able to read anything written on the book. Explain, why?
(ii) A lens of focal length 5 cm is being used by a student in the laboratory as a magnifying glass. His least distance of distinct vision is 25 cm. what magnification is the student getting?
State the cause of dispersion of white light passing through a glass prism. How did Newton show that white light of Sun contains seven colours using two identical glass prisms? Draw a ray diagram to show the path of light when two identical glass prisms are arranged together in inverted position with respect to each other and a narrow beam of white light is allowed to fall obliquely on one of the focus of the first prism.
A narrow beam PQ of white light is passing through a glass prism ABC as shown in the diagram.
Trace it on your answer sheet and show the path of the emergent beam as observed on the screen DE.
(i) Write the name and cause of the phenomenon observed.
(ii) Where else in nature is this phenomenon observed?
(iii) Based on this observaiton, state the conclusion which can be drawn about the constituents of white light.
Study the diagram given below and answer the questions that follows:
(i) Which defect of vision is represented in this case? Give reason for your answer.
(ii) What could be the two causes of this defect?
(iii) With the help of a diagram show how this defect can be corrected by the use of a suitable lens?
(i) List three common refractive defects of vision. Suggest the way of correcting these defects.
(ii) About 45 lac people in the developing countries are suffering from corneal blindness. About 30 lac children below the age of 12 yr suffering from this defect can be cured by replacing the defective cornea with the cornea of a donated eye. How and why can students of your age involve themselves to create awareness about this fact among people?
What is atmospheric refraction? use this phenomenon to explain the following natural events.
(i) Twinkling of stars
(ii) Advanced sunrise and delayed sunset
Draw diagrams to illustrate your answers.
What is meant by scattering of light? Mention the factor On which it depends. Explain, why the colour of the Clear sky is blue? An astronaut in space finds sky to be dark. Explain reason for this observation.
(i) Demonstrate an activity with a well labelled diagram to prove that while light is made up of seven colours.
(ii) Which colour of light bends least and which one the most while passing out from the prism? Also state the reason for the same.
(i) State two main causes of a person developing near sightedness. With the help of a ray diagram, suggest how he can be helped to overcome his disability ?
(ii) The far point of myopic person is 100 cm in front of the eye. Calculate the focal length and power of a lens required to enable him to see distant objects clearly.
For the figure ABCDE shows the path of a ray of red light through a raindrop. Assume that a ray of blue light is also incident along AB.
(i) Complete the diagram showing a possible path for the blue light through the raindrop.
(ii) Explain, why the paths followed by the red and blue light are different?
Why does white light split into different colours when passes through a glass prism?
What is the angle of emergence of a prism? If the emergent ray makes an angles of 45 with the second refracting surface of the prism?
Mention some precautions that should be taken while doing the experiment on tracing the path of the ray of light through a glass prism?
What does the white light not split into different colours when it passes through a glass slab?
On the rainy day, Ram reached his grandfather's place in village. On the way to house he saw a beautiful rainbow in the sky. In night, he saw lots of twinkling stars in the clear sky. He was very excited to see this beautiful natural phenomenon, which he was not able to see in the city, where he lived with his father?
Read the given passage and answer the following questions:
(i) Do you think pollution in Sunospne affects the formation of rainbow anc twinkling of stars?
(ii) Do you agree with the fact that pollution free environment will strengthen such natural phenomena In the cities as well?
(iii) What value is associated with given passage?
Archana and Anupurna are best friends and they are studying in the same class. Archana was facing difficulty in reading from the blackboard sitting at the last bench. Then, Anupurna wonders why Archana avoids sitting on the last bench, Archana was fond of eating junk foods at lunch time. But Anupurna started sharing lunch with Archana which contains green vegetables and fruits, Archana is now better and also started taking balanced diet.
As Read the above text and answer following questions:
(i) Name the eye defect which Archana is suffering from.
(ii) Name the two possible deformities related to her eye defect.
(iii) What value is shown by Anupurna?
For a class, the physics teacher told her students that our eyes can live even after our death. She told them that by donating our eyes after we die, one pair of our eyes can give vision to two corneal blind people. Eye donors may belong from either sex or any age group. People who are suffering from diabetes, hypertension, asthma or any other non-communicable disease can donate eyes. Eye banks have been established for this purpose, where you can pledge to donate your eyes after your death?
Read the given passage and answer the following questions:
(i) Is it possible that people using spectacles or those who have been operated for cataract donate their eyes?
(ii) Why is the pledge necessary?
(iii) Do you intend to make such a pledge? why?
Write the importance of ciliary muscles in the human eye. Name the defect of vision that arises due to the gradual weakening of the ciliary muscles. What types of lenses are required by the person suffering from this defect to see the objects clearly?
Akshay, sitting in the last row in his class, could not see clearly the words written on the blackboard. When the teacher noticed it he announced, if any student sitting in the front row could volunteer to exchange his seat with Akshay. Salman immediately agreed to exchange his seat with Akshay. He could now see the words written on the blackboard clearly. The teacher thought it fit to send the message to Akshay's parents advising them to get his eyesight checked.
Read the given passage and answer the following questions:
(i) which defect of vision is Akshay suffering from? wich type of lens is used to correct this defect?
(ii) State the values displayed by the teacher and Salman.
(iii) In your opinion, in what way can Akshay express his gratitude towards the teacher and Salman ?
(i) Write the function of each of the following pates of the human eye: Cornea, iris, crystalline lens, ciliary muscles.
(ii) Millions of people in the developing countries of the world are suffering from corneal blindness. These people can be cured by replacing the defective cornea with the cornea of a donated eye.
A charitable society of your city has organized a campaign in your neighborhood in order to create awareness about this fact.
If you are asked to participate in this mission how would you contribute To this
(a) State the objective of organizing such campaigns.
(b) List two arguments which you would give to motivate the people to donate their eyes after death.
(c) List two values which are developed in the persons who actively participate and contribute in such a programme.