{"id":88108,"date":"2025-06-01T07:01:42","date_gmt":"2025-06-01T07:01:42","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=88108"},"modified":"2025-06-01T07:01:42","modified_gmt":"2025-06-01T07:01:42","slug":"for-a-human-eye-where-u-is-the-distance-of-an-object-from-the-eye-f","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/for-a-human-eye-where-u-is-the-distance-of-an-object-from-the-eye-f\/","title":{"rendered":"For a human eye, where u is the distance of an object from the eye, f"},"content":{"rendered":"

For a human eye, where u is the distance of an object from the eye, f is the focal length of the lens and v is the distance of image from the eye, which is the correct schematic graph ?<\/p>\n

[amp_mcq option1=”[Graph (v vs u)]” option2=”[Graph (v vs u)]” option3=”[Graph (f vs u)]” option4=”[Graph (v vs f)]” correct=”option3″]<\/p>\n

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UPSC NDA-1 – 2024<\/div>\n<\/div>\n
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\nThe correct schematic graph for the human eye shows how the focal length (f) of the lens changes with the distance of the object (u). The distance of the image (v) from the lens to the retina is constant in a healthy eye. The lens formula relating these quantities is 1\/f = 1\/v + 1\/u (using magnitudes for a convex lens forming a real image). Since v is constant, as the object distance u increases, 1\/u decreases. For the equality to hold, 1\/f must also decrease, which means f must increase. Conversely, as u decreases, 1\/u increases, so 1\/f must increase, and f must decrease. The human eye’s lens changes its shape (accommodation) to adjust its focal length f to focus objects at different distances u onto the fixed retina distance v. The graph in option C shows f increasing as u increases, which is consistent with the lens formula and the process of accommodation.
\n<\/section>\n
\n– For the human eye, the image distance (v) is fixed (distance to the retina).
\n– The eye lens changes its focal length (f) to focus objects at different distances (u). This process is called accommodation.
\n– As the object distance (u) increases, the focal length (f) required to focus the image on the retina increases.
\n– The lens formula is 1\/f = 1\/v + 1\/u. With v constant, f is a function of u.
\n<\/section>\n
\nThe graph in option C shows f increasing with u. The functional relationship derived from the lens formula is f(u) = (v*u) \/ (v+u). The second derivative of this function with respect to u is negative, indicating the curve is concave down, which matches the shape depicted in graph C. Options A and B are incorrect because they show v varying with u, whereas v is constant. Option D shows v varying with f, which is also incorrect as v is constant.
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

For a human eye, where u is the distance of an object from the eye, f is the focal length of the lens and v is the distance of image from the eye, which is the correct schematic graph ? [amp_mcq option1=”[Graph (v vs u)]” option2=”[Graph (v vs u)]” option3=”[Graph (f vs u)]” option4=”[Graph (v … <\/p>\n

Detailed SolutionFor a human eye, where u is the distance of an object from the eye, f<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1093],"tags":[1103,1153,1128],"class_list":["post-88108","post","type-post","status-publish","format-standard","hentry","category-upsc-nda-1","tag-1103","tag-optics","tag-physics","no-featured-image-padding"],"yoast_head":"\nFor a human eye, where u is the distance of an object from the eye, f<\/title>\n<meta name=\"description\" content=\"The correct schematic graph for the human eye shows how the focal length (f) of the lens changes with the distance of the object (u). The distance of the image (v) from the lens to the retina is constant in a healthy eye. The lens formula relating these quantities is 1\/f = 1\/v + 1\/u (using magnitudes for a convex lens forming a real image). Since v is constant, as the object distance u increases, 1\/u decreases. For the equality to hold, 1\/f must also decrease, which means f must increase. Conversely, as u decreases, 1\/u increases, so 1\/f must increase, and f must decrease. The human eye's lens changes its shape (accommodation) to adjust its focal length f to focus objects at different distances u onto the fixed retina distance v. The graph in option C shows f increasing as u increases, which is consistent with the lens formula and the process of accommodation. - For the human eye, the image distance (v) is fixed (distance to the retina). - The eye lens changes its focal length (f) to focus objects at different distances (u). This process is called accommodation. - As the object distance (u) increases, the focal length (f) required to focus the image on the retina increases. - The lens formula is 1\/f = 1\/v + 1\/u. With v constant, f is a function of u.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/exam.pscnotes.com\/mcq\/for-a-human-eye-where-u-is-the-distance-of-an-object-from-the-eye-f\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"For a human eye, where u is the distance of an object from the eye, f\" \/>\n<meta property=\"og:description\" content=\"The correct schematic graph for the human eye shows how the focal length (f) of the lens changes with the distance of the object (u). The distance of the image (v) from the lens to the retina is constant in a healthy eye. The lens formula relating these quantities is 1\/f = 1\/v + 1\/u (using magnitudes for a convex lens forming a real image). Since v is constant, as the object distance u increases, 1\/u decreases. For the equality to hold, 1\/f must also decrease, which means f must increase. Conversely, as u decreases, 1\/u increases, so 1\/f must increase, and f must decrease. The human eye's lens changes its shape (accommodation) to adjust its focal length f to focus objects at different distances u onto the fixed retina distance v. The graph in option C shows f increasing as u increases, which is consistent with the lens formula and the process of accommodation. - For the human eye, the image distance (v) is fixed (distance to the retina). - The eye lens changes its focal length (f) to focus objects at different distances (u). This process is called accommodation. - As the object distance (u) increases, the focal length (f) required to focus the image on the retina increases. - The lens formula is 1\/f = 1\/v + 1\/u. With v constant, f is a function of u.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/for-a-human-eye-where-u-is-the-distance-of-an-object-from-the-eye-f\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T07:01:42+00:00\" \/>\n<meta name=\"author\" content=\"rawan239\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"rawan239\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"For a human eye, where u is the distance of an object from the eye, f","description":"The correct schematic graph for the human eye shows how the focal length (f) of the lens changes with the distance of the object (u). 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This process is called accommodation. - As the object distance (u) increases, the focal length (f) required to focus the image on the retina increases. - The lens formula is 1\/f = 1\/v + 1\/u. With v constant, f is a function of u.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/exam.pscnotes.com\/mcq\/for-a-human-eye-where-u-is-the-distance-of-an-object-from-the-eye-f\/","og_locale":"en_US","og_type":"article","og_title":"For a human eye, where u is the distance of an object from the eye, f","og_description":"The correct schematic graph for the human eye shows how the focal length (f) of the lens changes with the distance of the object (u). The distance of the image (v) from the lens to the retina is constant in a healthy eye. 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This process is called accommodation. - As the object distance (u) increases, the focal length (f) required to focus the image on the retina increases. - The lens formula is 1\/f = 1\/v + 1\/u. 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