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प्रश्न
Name the physical quantity whose unit is dioptre.
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उत्तर
The power of a lens is a physical quantity with dioptre as it's unit.
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संबंधित प्रश्न
Calculate the focal length of a corrective lens having power +2D.
A doctor has prescribed a corrective lens of power +1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?
You have two lenses A and B of focal lengths +10 cm and –10 cm, respectively. State the nature and power of each lens. Which of the two lenses will form a virtual and magnified image of an object placed 8 cm from the lens? Draw a ray diagram to justify your answer
The lens mentioned in 6(b) above is of focal length 25cm. Calculate the power of the lens.
Give the usual name for the following:
A point inside a lens through which the light passes undeviated.
Define power of a lens. Write its units. Deduce the relation `1/f =1/f_1 +1/f_2`for two thin lenses kept in contact coaxially.
Surabhi from std. X uses spectacle. The power of the lenses in her spectacle is 0.5 D.
Answer the following questions from the given information:
- Identify the type of lenses used in her spectacle.
- Identify the defect of vision Surabhi is suffering from.
- Find the focal length of the lenses used in her spectacle.
Complete the diagram to show the formation of the image of the object AB.
(i) Name the Lens LL’.
(ii) Where is the image of the object AB formed?
(iii) State three characteristics of the image.
The power of the magnifying glass depends on the distance of the magnifying glass from object.
Increase in the converging power of eye lens cause ‘hypermetropia'
Assertion and reasoning type
- Assertion: Myopia is due to the increase in the converging power of eye lens.
- Reason: Myopia can be corrected with the help of concave lens.
The SI unit of the power of a lens is the:
One dioptre is the power of a lens whose focal length is:
1 D is equivalent to:
The power of a lens in dioptres is given by:
A concave lens is a diverging lens whose focal length and power are both:
A positive power of a lens indicates a:
A convex lens has:
A concave lens has:
