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Q56
(CISF/2022)
Science & Technology › Basic Science (Physics, Chemistry, Biology)
Dioptre is the SI unit of :
Result
Your answer:
—
·
Correct:
C
Explanation
A dioptre (symbol: D) is the SI unit of the power of a lens or a curved mirror. The power of a lens (P) is defined as the reciprocal of its focal length (f) expressed in meters, represented by the formula P = 1/f. Therefore, 1 dioptre is equivalent to 1 m-1.
- Size: Measured in standard units of length like millimeters or centimeters.
- Curvature: While related to power, curvature is generally expressed as the reciprocal of the radius of curvature.
- Magnification: It is a ratio of the height of the image to the height of the object (or distances), making it a dimensionless quantity with no units.
By convention, the power of a converging (convex) lens is positive, while the power of a diverging (concave) lens is negative.
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