Q29.A symmetric thin biconvex lens is cut into four equal parts by two planes AB and CD as shown in figure. If the power of original lens is 4 D then the power of a part of the divided lens is (1) D (2) 8D (3) 2D (4) 4D
What This Question Tests
This question tests the understanding of how cutting a lens affects its focal length and thus its power, considering changes in curvature radii or effective aperture.
Concepts Tested
Formulas Used
1/f = (ฮผ-1)(1/R1 - 1/R2)
Power P = 1/f
๐ NCERT Sections This Tests
9.8 โ A Beam Of Light Converges At A Point P. Now A Lens Is Placed In The
Physics Class 12 ยท Chapter 9
9.8 A beam of light converges at a point P. Now a lens is placed in the path of the convergent beam 12cm from P. At what point does the beam converge if the lens is (a) a convex lens of focal length 20cm, and (b) a concave lens of focal length 16cm?
9.19 โ A Screen Is Placed 90Cm From An Object. The Image Of The Object On
Physics Class 12 ยท Chapter 9
9.19 A screen is placed 90cm from an object. The image of the object on the screen is formed by a convex lens at two different locations separated by 20cm. Determine the focal length of the lens.
9.7 โ Double-Convex Lenses Are To Be Manufactured From A Glass Of
Physics Class 12 ยท Chapter 9
9.7 Double-convex lenses are to be manufactured from a glass of refractive index 1.55, with both faces of the same radius of curvature. What is the radius of curvature required if the focal length is to be 20cm?
๐ Question Details
- Chapter
- Ray Optics
- Topic
- Power of a Lens
- Year
- 2025
- Shift
- 22 Jan Shift 2
- Q Number
- Q29
- Type
- MCQ
- NCERT Ref
- Class 12 Physics Ch 9: Ray Optics and Optical Instruments
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