A convex lens is used to form an image of an | vedclass

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(D) When a lens is used to form an image,every point on the lens contributes to the formation of the entire image. If the upper half of the lens is bl

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the brightness of the image reduces

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(D) When a lens is used to form an image,every point on the lens contributes to the formation of the entire image. If the upper half of the lens is blackened,the light rays passing through that portion are blocked. However,the remaining lower half of the lens still allows light rays from all parts of the object to pass through and converge at the same focal point. Consequently,the complete image is still formed at the same position on the screen. Since the amount of light reaching the screen is reduced (as half the aperture is blocked),the intensity or brightness of the image decreases.

$A$ convex lens is used to form an image of an object on a screen. If the upper half of the lens is blackened,so that it becomes opaque,then

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