Q1. When you look at an object very close to your eyes, the:
(A) Ciliary muscles of your eye contract and the eye lens becomes thick.
(B) Ciliary muscles of your eye get relaxed and the eye lens becomes thick.
(C) Ciliary muscles of your eye contract and the eye lens becomes thin.
(D) Ciliary muscles of your eye get relaxed and the eye lens becomes thin. [1 Mark]

Q2. The pair of eye parts responsible for admitting different amounts of light into the eyes is:
(A) Iris and pupil (B) Ciliary muscles and pupil (C) Retina and Iris (D) Ciliary muscles and cornea [1 Mark]

Q3. The lens system of the human eye forms an image on a light-sensitive screen, which is called as:
(A) Cornea (B) Ciliary muscles (C) Optic nerves (D) Retina [1 Mark]

Q4. The part of the human eye which controls the amount of light entering into it:
(A) Iris (B) Cornea (C) Ciliary muscles (D) Pupil [1 Mark]

Q5. Most of the refraction for the light rays entering the eye occurs at:
(A) Iris (B) Pupil (C) Crystalline lens (D) Outer surface of Cornea [1 Mark]

Q6. The curvature of the eye lens of the human eye:
(A) is fixed. (B) can be increased. (C) can be decreased. (D) increases or decreases as the case may be. [1 Mark]

Q7. What is a pupil? [1 Mark]

Q8. Name the condition resulting due to the eye lens becoming cloudy. [1 Mark]

Q9. State (i) the near point and (ii) the far point of vision of a normal adult person. [1 Mark]

Q10. (i) How does the change in curvature of the eye lens help us in the process of seeing nearby objects clearly? (ii) State the range of the power of accommodation of a normal human eye. [2 Marks]

Q11. How does the focal length of the eye lens change as the distance of the object from the eye is altered? Explain. [2 Marks]

Q12. State the role of ciliary muscles in the accommodation of the eye. [2 Marks]

Q13. (a) What is the function of the iris and pupil of the eye? (b) How does the focal length of the eye lens change as per the distance of the object in front of the eye? [2 Marks]

Q14. Define the term 'power of accommodation' of the human eye. Write the name of the part of the eye which plays a major role in the process of accommodation and explain what happens when the human eye focuses on (i) nearby objects and (ii) distant objects. [3 Marks]

Q15. Define the term power of accommodation. Write the modification in the curvature of the eye which enables us to see nearby objects. What are the limits of the accommodation power of a healthy normal human eye? [3 Marks]

Q16. What happens to the image distance in the normal human eye when we decrease the distance of an object from, say, 10 m to 1 m? Justify your answer. [3 Marks]

Q17. Write the function of each of the following parts of the human eye: (i) Cornea (ii) Iris (iii) Crystalline lens (iv) Ciliary muscles. [2 Marks]

Q18. Assertion (A): Myopic eye cannot see distant objects distinctly.
Reason (R): For the correction of myopia, converging lenses of appropriate power are prescribed by eye-surgeons.
(A) Both A and R are true and R is the correct explanation of A.
(B) Both A and R are true, but R is not the correct explanation of A.
(C) A is true, but R is false.
(D) A is false, but R is true. [1 Mark]

Q19. An old person is suffering from an eye defect caused by weakening of ciliary muscles and diminishing flexibility of the eye lens. If the defect of vision is 'a' which can be corrected by lens 'b', then 'a' and 'b' respectively are:
(a) hypermetropia and convex lens (b) presbyopia and bifocal lens (c) myopia and concave lens (d) myopia and bifocal lens [1 Mark]

Q20. To restore clear vision in persons whose size of the eyeball has reduced, he/she is suggested to use a suitable:
(A) Converging lens (B) Diverging lens (C) Bifocal lens (D) Cylindrical lens [1 Mark]

Q21. The possible way to restore clear vision of those people whose eyeball has elongated is the use of a suitable:
(a) bifocal lens (b) concave lens (c) converging lens (d) convex lens [1 Mark]

Q22. Name two possible causes of myopia. [1 Mark]

Q23. An old person is unable to see nearby objects as well as distant objects clearly. What defect of vision is he suffering from? [1 Mark]

Q24. Priya prefers to sit in the front row as she finds it difficult to read the blackboard from the last desk in her classroom. State the defect of vision she is suffering from. [1 Mark]

Q25. A person has to keep reading material much beyond 25 cm (say at 50 cm) from the eye for comfortable reading. Name the defect of vision he is suffering from. List two causes responsible for the arising of this defect. Draw a labelled diagram showing correction of this defect using eye-glasses. Are these glasses convergent or divergent? [3 Marks]

Q26. A person uses lenses of power +2.0 D in his spectacles for the correction of his vision. (a) Name the defect of vision the person is suffering from. (b) List two causes of this defect. (c) Determine the focal length of the lenses used in the spectacles. [3 Marks]

Q27. A person uses lenses of power −0.5 D in his spectacles for the correction of his vision. (a) Name the defect of vision the person is suffering from. (b) List two causes of this defect. (c) Determine the focal length of the lenses used in the spectacles. [3 Marks]

Q28. When do we consider a person to be myopic? List two causes of this defect. Explain, using a ray diagram, how this defect of the eye can be corrected. [3 Marks]

Q29. Name two defects of vision. Mention their cause and the type of lenses used to correct them. [3 Marks]

Q30. What eye defect is hypermetropia? What are its two possible causes? Describe, with a ray diagram, how this defect of vision can be corrected by using an appropriate lens. [3 Marks]

Q31. Due to the gradual weakening of ciliary muscles and diminishing flexibility of the eye lens, a certain defect of vision arises. Write the name of this defect. Name the type of lens required by such persons to improve their vision. Explain the structure and function of such a lens. [3 Marks]

Q32. It is observed that the power of an eye to see nearby objects as well as far-off objects diminishes with age. (A) Give a reason for the above statement. (B) Name the defect that is likely to arise in the eyes in such a condition. (C) Draw a labelled ray diagram to show the type of corrective lens used for restoring the vision of such an eye. [3 Marks]

Q33. Name the type of defect of vision a person is suffering from if he uses convex lenses in his spectacles for the correction of his vision. If the power of the lenses is +0.5 D, find the focal length of the lenses. [3 Marks]

Q34. Assertion (A): When rays of white light pass through a prism, on emerging they give a spectrum of seven colours.
Reason (R): It is due to the scattering of light that red light bends minimum and violet light bends the maximum.
(A) Both A and R are true and R is the correct explanation.
(B) Both A and R are true, but R is not the correct explanation.
(C) A is true, but R is false.
(D) A is false, but R is true. [1 Mark]

Q35. A thin beam of white light falls on a face of a glass prism and a spectrum is obtained on a screen. Which of the following options is the correct sequence of colours from top to bottom on the screen?
(A) Red, Green, Yellow, Violet, Blue (B) Red, Yellow, Green, Blue, Violet (C) Violet, Blue, Green, Yellow, Red (D) Violet, Red, Green, Yellow, Blue [1 Mark]

Q36. Assertion (A): White light is dispersed by a glass prism into seven colours.
Reason (R): The red light bends the least while the violet bends the most when a beam of white light passes through a glass prism.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true. [1 Mark]

Q37. A student traces the path of a ray of light through a glass prism for different angles of incidence. He draws the following conclusions:
(I) On entering the prism, the light ray bends towards its base.
(II) The light ray suffers refraction at the point of incidence and point of emergence.
(III) The emergent ray bends at a certain angle to the direction of the incident ray.
(IV) While emerging from the prism, the light ray bends towards the vertex of the prism.
The correct inferences are:
(a) I, II and III (b) I, III and IV (c) II, III and IV (d) I and IV [1 Mark]

Q38. Name the component of white light that deviates (i) the least and (ii) the most while passing through a glass prism. [1 Mark]

Q39. What is the dispersion of light? [1 Mark]

Q40. Define the term dispersion of white light. State the colour which bends (i) the most, and (ii) the least while passing through a glass prism. Draw a diagram to show the dispersion of white light. [3 Marks]

Q41. What is dispersion of white light? Draw a neat diagram to show the dispersion of white light by a glass prism. What is the cause of dispersion? [3 Marks]

Q42. Describe an activity to show that the colours of white light split by a glass prism can be recombined to get white light by another identical glass prism. Also, draw a ray diagram to show the recombination of the spectrum of white light. [3 Marks]

Q43. State the cause of dispersion of white light by a glass prism. How did Newton, using two identical glass prisms, show that white light is made of seven colours? Draw a ray diagram to show the path of a narrow beam of white light through a combination of two identical prisms arranged in an inverted position with respect to each other. [5 Marks]

Q44. What is dispersion of white light? State its cause. Draw a diagram to show the dispersion of a beam of white light by a glass prism. [2 Marks]

Q45. Give any one instance, other than a prism, in which the spectrum of white light is observed. What happens to white light when it passes through a glass prism? [1 Mark]

Q46. Assertion (A): The rainbow is a natural spectrum of sunlight in the sky.
Reason (R): Rainbow is formed in the sky when the sun is overhead and water droplets are also present in the air.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true. [1 Mark]

Q47. What is atmospheric refraction? Briefly explain. Why does the apparent position of a star appear different from its true position? [3 Marks]

Q48. The stars appear higher above the horizon than they actually are. Explain why this is so. [3 Marks]

Q49. Explain why the planets do not twinkle but the stars twinkle. [3 Marks]

Q50. Explain, with the help of a diagram, how we are able to observe the sunrise about two minutes before the sun actually rises above the horizon. Hence, explain why the apparent duration of a day from sunrise to sunset is about 4 minutes more than its actual duration. [3 Marks]

Q51. What is atmospheric refraction? Use this phenomenon to explain the following natural events: (a) Twinkling of stars (b) Advanced sunrise and delayed sunset. Draw diagrams to illustrate your answers. [5 Marks]

Q52. (a) With the help of a diagram, explain Isaac Newton's experiment that led to the idea that sunlight is made up of seven colours. (b) What is atmospheric refraction? List two natural phenomena based on atmospheric refraction. [2 Marks]

Q53. What is a rainbow? Draw a labelled diagram to show the formation of a rainbow. [3 Marks]

Q54. The students in a class took a thick cardboard sheet and made a small hole at its centre. Sunlight was allowed to fall on this small hole, obtaining a narrow beam of white light. A glass prism was taken and this white light was made to fall on one of its faces; the prism was turned until the light emerging from the opposite face appeared on a nearby screen as a beautiful band of colours — the spectrum of white light.
(i) Give one more instance in which this type of spectrum is observed.
(ii) What happens to white light in the above case?
(iii) List two conditions necessary to observe a rainbow. [3 Marks]

Q55. "Rainbow is an example of dispersion of sunlight." Justify this statement by explaining, with the help of a labelled diagram, the formation of a rainbow in the sky. List two essential conditions for observing a rainbow. [5 Marks]

Q56. Draw a ray diagram to show the formation of a rainbow in the sky. On the diagram, mark A — where dispersion of light occurs, B — where internal reflection of light occurs, and C — where final refraction of light occurs. List two necessary conditions to observe a rainbow. [2 Marks]

Q57. Assertion (A): Sky appears blue in the day time.
Reason (R): White light is composed of seven colours.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true, and R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true. [1 Mark]

Q58. Which of the following statements is NOT true for the scattering of light?
(a) Colour of the scattered light depends on the size of particles of the atmosphere.
(b) Red light is least scattered in the atmosphere.
(c) Scattering of light takes place as various colours of white light travel with different speeds in air.
(d) Fine particles in the atmosphere scatter blue light more strongly than red, so scattered blue light enters our eyes. [1 Mark]

Q59. When a beam of white light passes through a region having very fine dust particles, the colour of light mainly scattered in that region is:
(a) Red (b) Orange (c) Blue (d) Yellow [1 Mark]

Q60. Assertion (A): Red light signals are used to stop vehicles on the road.
Reason (R): Red coloured light is scattered the most so as to be visible from a large distance.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true and R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true. [1 Mark]

Q61. List the factors on which the scattering of light depends. [1 Mark]

Q62. Why is the red colour selected for danger signal lights? [1 Mark]

Q63. What will be the colour of the sky when it is observed from a place in the absence of any atmosphere? [1 Mark]

Q64. What is the Tyndall effect? Why is it shown by colloidal particles? State four instances of observing the Tyndall effect. [3 Marks]

Q65. What is scattering of light? Why is the colour of the clear sky blue? Explain. [3 Marks]

Q66. Give reasons: (i) The sky appears dark to passengers flying at very high altitude. (ii) 'Danger' signal lights are red in colour. [2 Marks]

Q67. Give reasons for the following: (A) Danger signals installed at airports and at the top of tall buildings are of red colour. (B) The sky appears dark to passengers flying at very high altitudes. (C) The path of a beam of light passing through a colloidal solution is visible. [3 Marks]

Q68. The colour of the clear sky, as seen from the Earth, appears blue, but from space it appears black. Why? [2 Marks]

Q69. Name and explain the phenomenon of light due to which the path of a beam of light becomes visible when it enters a smoke-filled room through a small hole. Also state the dependence of the colour of light we receive on the size of the particles of the medium through which the beam passes. [3 Marks]

Q70. (a) Write the function of the cornea and the iris of the human eye. (b) Why does the sun appear reddish early in the morning? Will this phenomenon be observed by an astronaut standing on the Moon? Give a reason to justify your answer. [3 Marks]

Q71. Why does the sun appear reddish early in the morning? Explain with the help of a labelled diagram. [3 Marks]

Q72. Consider the following statements about the human eye: (A) The diameter of the eyeball is about 2.3 cm. (B) The iris is a dark muscular diaphragm that controls the size of the pupil. (C) Most of the refraction for light rays entering the eye occurs at the crystalline lens. (D) While focusing on objects at different distances, the distance between the crystalline lens and the retina is adjusted by the ciliary muscles.
The correct statements are:
(a) A and B (b) A, B and C (c) B, C and D (d) A, C and D [1 Mark]

Q73. (A) State the role of ciliary muscles present in our eye. (B) Identify the defect of vision in each of the given cases and suggest its corrective measure: (i) The eye lens has become milky and cloudy. (ii) The eye lens has excessive curvature. (iii) The eye lens has too large a focal length (longer than normal). (iv) Ciliary muscles have weakened. [3 Marks]

Q74. Varun, instead of copying from the blackboard, used to copy regularly from the notebook of his friend Sudhir, with whom he sat on the same desk. Sudhir told the teacher about it. The teacher asked Varun to get his eyes checked by a doctor.
(A) In your view, what is wrong with Varun's eyes and how can it be corrected?
(B) If the doctor prescribes Varun lenses of power −0.5 D, what is the type of lens?
(C) What values are displayed by Sudhir and the teacher in this situation? [3 Marks]

Q75. A student sitting at the back bench in a class has difficulty reading the blackboard. State two possible causes of this defect and name the type of lens used to correct it. [2 Marks]

Q76. Name two natural phenomena that are explained by atmospheric refraction. [1 Mark]

Q77. What is the function of the retina in the human eye? [1 Mark]

Q78. What is the function of the crystalline lens of the eye? [1 Mark]

Q79. Write the function of the iris in the human eye. [1 Mark]