Name some other defects of eye.

Name the 3 layers of eye

Give two possible reasons for defect of the eye in human beings.

A person is unable to see objects distinctly placed within 50 cm from his eyes. (a) Name the defect of vision the person is suffering from and list its two possible causes. (b) Draw ray diagram to show the defect in the above case. (c) Mention the type of lens used by him for the correction of the defect and calculate its power. Assume that the near point for the normal eye is 25 cm. (d) Draw a labelled diagram for the correction of the defect in the above case.

A person cannot see distinctly the book placed nearer than 60 cm from his eyes. (i) Name the defect of vision the person is suffering from. (ii) List two possible causes of this defect. (iii) Draw a ray diagram to show this vision defect. (iv) How can this defect be corrected ? (v) Draw a ray diagram to show the correction of this defect.

Name some bacterial disease.

Given below is a diagram depicting a defect of the human eye. Study the same and then answer the questions that follow: Name two possible reasons for this defect of the eye in human beings.

Given below is a diagram depicting a defect of the human eye. Study the same and then answer the questions that follow: Name the defect shown in the diagram.

Consider the figure of a defective crystal : (a) Name the defect shown by this diagram. (b) What is the effect of this defect on the solid ? (c) Name as ionic compound which can show this type of defect.

Given below is a diagram depicting a defect of the human eye, study the same and then answer the questions that follow: (i) Name the defect shown in the diagram. (ii) What are the two possible reasons that cause this defect? (iii) Name the type of lens used to correct this defect. (iv) With the help of a diagram show how the defect shown above is rectified using a suitable lens.

Nooper needs a lens of power - 4.5 D for correction of her vision. (a) What kind of defect in vision is she suffering from ? (b) What is the focal length and nature of corrective lens ? ( c) Draw ray diagrams showing the defected eye and correction for the defect. (d) What are the causes of this defect ?