A thin lens focal length ${{f}_{1}}$ and its aperture has diameter d. It forms an image of intensity I. Now the central part of the aperture upto diameter $\frac{d}{2}$ is blocked by an opaque paper. The focal length and image intensity will change to

Question

Accepted Answer

$f$ and $\frac{3I}{4}$

Answer

$\frac{f}{2}$ and $\frac{I}{2}$

Answer

$f$ and $\frac{I}{4}$

Answer

$\frac{3f}{4}$ and $\frac{I}{2}$

Ray Optics and Optical Instruments

Question: A thin lens focal length ${{f}_{1}}$ and its aperture has diameter d. It forms an image of intensity I. Now the central part of the aperture upto diameter $\frac{d}{2}$ is blocked by an opaque paper. The focal length and image intensity will change to

Ray Optics and Optical Instruments

Question: A thin lens focal length ${{f}_{1}}$ and its aperture has diameter d. It forms an image of intensity I. Now the central part of the aperture upto diameter $\frac{d}{2}$ is blocked by an opaque paper. The focal length and image intensity will change to

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