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प्रश्न
State the condition for the following a ray passes undeviated through the lens .
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उत्तर
If a ray passes undeviated through the lens it is incident at the optical centre of the lens.
संबंधित प्रश्न
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
What is the nature of a lens whose power is, −4 D?
A convex lens of power 5 D and a concave lens of power 7.5 D are placed in contact with each other. What is the :
(a) power of this combination of lenses?
(b) focal length of this combination of lenses?
Two lenses A and B have focal lengths of +20 cm and, −10 cm, respectively.
(a) What is the nature of lens A and lens B?
(b) What is the power of lens A and lens B?
(c) What is the power of combination if lenses A and B are held close together?
What is the unit of power of a lens? Define the unit of power of a lens.
State the condition for the following a lens has both its focal lengths equal .
Express the power (with sign) of a concave lens of focal length 20 cm.
Consider the situation described in the previous problem. Where should a point source be placed on the principal axis so that the two images form at the same place?
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.
The SI unit of the power of a lens is the:
