Qstnid -I-15-two Converging Lenses Of Unequal Focal Lengths Can Be Used To Reduce The Aperture Of A Parallel Beam Of Light Without Loosing The Energy Of The Light. This Increase The Intensity. Describe How The Converging Lenses Should Be Placed To Do This. - 18: Geometrical Optics - Neet-xii-physics

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NEET-XII-Physics

18: Geometrical Optics

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#15
Two converging lenses of unequal focal lengths can be used to reduce the aperture of a parallel beam of light without loosing the energy of the light. This increase the intensity. Describe how the converging lenses should be placed to do this.
Ans : Let the two converging lenses be L₁ and L₂, with focal lengths f₁ and f₂ respectively.
To reduce the aperture of a parallel beam of light without losing the energy of the light and also increase the intensity, we have to place the lens L₂ within the focal range of L_1.

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