Q27.Two identical symmetric double convex lenses of focal length f are cut into two equal parts L1, L2 by AB plane and L3, L4 by XY plane as shown in figure respectively. The ratio of focal lengths of lenses L1 and L3 is (1) 1:1 (2) 1:2 (3) 1:4 (4) 2:1
What This Question Tests
The question assesses the knowledge of how the focal length of a lens changes when it is cut in different ways, specifically comparing the focal lengths of a plano-convex lens and a half-cut biconvex lens.
Concepts Tested
Formulas Used
1/f = (ฮผ-1)(1/R1 - 1/R2)
๐ NCERT Sections This Tests
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?
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.
๐ Question Details
- Chapter
- Ray Optics
- Topic
- Lens Maker's Formula and cutting of lenses
- Year
- 2025
- Shift
- 29 Jan Shift 2
- Q Number
- Q27
- Type
- MCQ
- NCERT Ref
- Class 12 Physics Ch 9: Ray Optics and Optical Instruments
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