{"id":88146,"date":"2025-06-01T07:03:24","date_gmt":"2025-06-01T07:03:24","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=88146"},"modified":"2025-06-01T07:03:24","modified_gmt":"2025-06-01T07:03:24","slug":"which-one-of-the-following-statements-is-not-correct-29","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-is-not-correct-29\/","title":{"rendered":"Which one of the following statements is not correct?"},"content":{"rendered":"

Which one of the following statements is not<\/i> correct?<\/p>\n

[amp_mcq option1=”The radius of curvature of a concave mirror is twice its focal length” option2=”Power of a convex lens is negative and that of a concave lens is positive” option3=”The radius of curvature of a plane mirror is infinity” option4=”When a ray of light passes from an optically denser medium to an optically rarer medium, the angle of refraction is greater than the corresponding angle of incidence” correct=”option2″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC NDA-2 – 2015<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nThe correct answer is B. The statement about the power of convex and concave lenses is incorrect.
\n<\/section>\n
\n– Statement A is correct. For a spherical mirror, the radius of curvature (R) is twice the focal length (f), i.e., R = 2f.
\n– Statement B is incorrect. The power of a lens (P = 1\/f) is positive for a converging lens (convex lens) because its focal length (f) is positive. The power of a diverging lens (concave lens) is negative because its focal length (f) is negative.
\n– Statement C is correct. A plane mirror can be considered as a part of a spherical mirror with an infinite radius of curvature. Consequently, its focal length (f = R\/2) is also infinite.
\n– Statement D is correct. According to Snell’s Law, when light travels from a denser medium (higher refractive index n\u2081) to a rarer medium (lower refractive index n\u2082), it bends away from the normal. This means the angle of refraction (\u03b8\u2082) is greater than the angle of incidence (\u03b8\u2081), as n\u2081 sin \u03b8\u2081 = n\u2082 sin \u03b8\u2082 and n\u2081 > n\u2082, implies sin \u03b8\u2082 > sin \u03b8\u2081, leading to \u03b8\u2082 > \u03b8\u2081.
\n<\/section>\n
\nThe power of a lens is a measure of its ability to converge or diverge light rays. It is expressed in dioptres (D), where 1 D = 1 m\u207b\u00b9. Convex lenses are used to correct hypermetropia (long-sightedness), and concave lenses are used to correct myopia (short-sightedness).
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

Which one of the following statements is not correct? [amp_mcq option1=”The radius of curvature of a concave mirror is twice its focal length” option2=”Power of a convex lens is negative and that of a concave lens is positive” option3=”The radius of curvature of a plane mirror is infinity” option4=”When a ray of light passes from … <\/p>\n

Detailed SolutionWhich one of the following statements is not correct?<\/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":[1094],"tags":[1443,1153,1128],"class_list":["post-88146","post","type-post","status-publish","format-standard","hentry","category-upsc-nda-2","tag-1443","tag-optics","tag-physics","no-featured-image-padding"],"yoast_head":"\nWhich one of the following statements is not correct?<\/title>\n<meta name=\"description\" content=\"The correct answer is B. The statement about the power of convex and concave lenses is incorrect. - Statement A is correct. For a spherical mirror, the radius of curvature (R) is twice the focal length (f), i.e., R = 2f. - Statement B is incorrect. The power of a lens (P = 1\/f) is positive for a converging lens (convex lens) because its focal length (f) is positive. The power of a diverging lens (concave lens) is negative because its focal length (f) is negative. - Statement C is correct. A plane mirror can be considered as a part of a spherical mirror with an infinite radius of curvature. Consequently, its focal length (f = R\/2) is also infinite. - Statement D is correct. According to Snell's Law, when light travels from a denser medium (higher refractive index n\u2081) to a rarer medium (lower refractive index n\u2082), it bends away from the normal. This means the angle of refraction (\u03b8\u2082) is greater than the angle of incidence (\u03b8\u2081), as n\u2081 sin \u03b8\u2081 = n\u2082 sin \u03b8\u2082 and n\u2081 > n\u2082, implies sin \u03b8\u2082 > sin \u03b8\u2081, leading to \u03b8\u2082 > \u03b8\u2081.\" \/>\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\/which-one-of-the-following-statements-is-not-correct-29\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Which one of the following statements is not correct?\" \/>\n<meta property=\"og:description\" content=\"The correct answer is B. The statement about the power of convex and concave lenses is incorrect. - Statement A is correct. For a spherical mirror, the radius of curvature (R) is twice the focal length (f), i.e., R = 2f. - Statement B is incorrect. The power of a lens (P = 1\/f) is positive for a converging lens (convex lens) because its focal length (f) is positive. The power of a diverging lens (concave lens) is negative because its focal length (f) is negative. - Statement C is correct. A plane mirror can be considered as a part of a spherical mirror with an infinite radius of curvature. Consequently, its focal length (f = R\/2) is also infinite. - Statement D is correct. According to Snell's Law, when light travels from a denser medium (higher refractive index n\u2081) to a rarer medium (lower refractive index n\u2082), it bends away from the normal. This means the angle of refraction (\u03b8\u2082) is greater than the angle of incidence (\u03b8\u2081), as n\u2081 sin \u03b8\u2081 = n\u2082 sin \u03b8\u2082 and n\u2081 > n\u2082, implies sin \u03b8\u2082 > sin \u03b8\u2081, leading to \u03b8\u2082 > \u03b8\u2081.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-is-not-correct-29\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T07:03:24+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":"Which one of the following statements is not correct?","description":"The correct answer is B. The statement about the power of convex and concave lenses is incorrect. - Statement A is correct. For a spherical mirror, the radius of curvature (R) is twice the focal length (f), i.e., R = 2f. - Statement B is incorrect. The power of a lens (P = 1\/f) is positive for a converging lens (convex lens) because its focal length (f) is positive. The power of a diverging lens (concave lens) is negative because its focal length (f) is negative. - Statement C is correct. A plane mirror can be considered as a part of a spherical mirror with an infinite radius of curvature. Consequently, its focal length (f = R\/2) is also infinite. - Statement D is correct. According to Snell's Law, when light travels from a denser medium (higher refractive index n\u2081) to a rarer medium (lower refractive index n\u2082), it bends away from the normal. This means the angle of refraction (\u03b8\u2082) is greater than the angle of incidence (\u03b8\u2081), as n\u2081 sin \u03b8\u2081 = n\u2082 sin \u03b8\u2082 and n\u2081 > n\u2082, implies sin \u03b8\u2082 > sin \u03b8\u2081, leading to \u03b8\u2082 > \u03b8\u2081.","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\/which-one-of-the-following-statements-is-not-correct-29\/","og_locale":"en_US","og_type":"article","og_title":"Which one of the following statements is not correct?","og_description":"The correct answer is B. The statement about the power of convex and concave lenses is incorrect. - Statement A is correct. For a spherical mirror, the radius of curvature (R) is twice the focal length (f), i.e., R = 2f. - Statement B is incorrect. The power of a lens (P = 1\/f) is positive for a converging lens (convex lens) because its focal length (f) is positive. The power of a diverging lens (concave lens) is negative because its focal length (f) is negative. - Statement C is correct. A plane mirror can be considered as a part of a spherical mirror with an infinite radius of curvature. Consequently, its focal length (f = R\/2) is also infinite. - Statement D is correct. According to Snell's Law, when light travels from a denser medium (higher refractive index n\u2081) to a rarer medium (lower refractive index n\u2082), it bends away from the normal. This means the angle of refraction (\u03b8\u2082) is greater than the angle of incidence (\u03b8\u2081), as n\u2081 sin \u03b8\u2081 = n\u2082 sin \u03b8\u2082 and n\u2081 > n\u2082, implies sin \u03b8\u2082 > sin \u03b8\u2081, leading to \u03b8\u2082 > \u03b8\u2081.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-is-not-correct-29\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T07:03:24+00:00","author":"rawan239","twitter_card":"summary_large_image","twitter_misc":{"Written by":"rawan239","Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-is-not-correct-29\/","url":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-is-not-correct-29\/","name":"Which one of the following statements is not correct?","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T07:03:24+00:00","dateModified":"2025-06-01T07:03:24+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"The correct answer is B. 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This means the angle of refraction (\u03b8\u2082) is greater than the angle of incidence (\u03b8\u2081), as n\u2081 sin \u03b8\u2081 = n\u2082 sin \u03b8\u2082 and n\u2081 > n\u2082, implies sin \u03b8\u2082 > sin \u03b8\u2081, leading to \u03b8\u2082 > \u03b8\u2081.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-is-not-correct-29\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-is-not-correct-29\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-statements-is-not-correct-29\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/exam.pscnotes.com\/mcq\/"},{"@type":"ListItem","position":2,"name":"UPSC NDA-2","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/upsc-nda-2\/"},{"@type":"ListItem","position":3,"name":"Which one of the following statements is not correct?"}]},{"@type":"WebSite","@id":"https:\/\/exam.pscnotes.com\/mcq\/#website","url":"https:\/\/exam.pscnotes.com\/mcq\/","name":"MCQ and Quiz for Exams","description":"","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/exam.pscnotes.com\/mcq\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209","name":"rawan239","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/image\/","url":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","caption":"rawan239"},"sameAs":["https:\/\/exam.pscnotes.com"],"url":"https:\/\/exam.pscnotes.com\/mcq\/author\/rawan239\/"}]}},"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/88146","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/comments?post=88146"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/88146\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=88146"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=88146"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=88146"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}