{"id":88901,"date":"2025-06-01T07:24:27","date_gmt":"2025-06-01T07:24:27","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=88901"},"modified":"2025-06-01T07:24:27","modified_gmt":"2025-06-01T07:24:27","slug":"two-convex-lenses-have-focal-lengths-of-50-cm-and-25-cm-respectively","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/two-convex-lenses-have-focal-lengths-of-50-cm-and-25-cm-respectively\/","title":{"rendered":"Two convex lenses have focal lengths of 50 cm and 25 cm, respectively."},"content":{"rendered":"

Two convex lenses have focal lengths of 50 cm and 25 cm, respectively. If these two lenses are placed in contact, then the net power of this combination will be equal to<\/p>\n

[amp_mcq option1=”+2 dioptre” option2=”+6 dioptre” option3=”-6 dioptre” option4=”+3 dioptre” correct=”option2″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC NDA-2 – 2022<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
The power of a lens (P) is the reciprocal of its focal length (f) in meters (P = 1\/f). For a combination of thin lenses in contact, the total power (P_net) is the sum of the individual powers (P_net = P1 + P2 + …).
\nGiven focal lengths: f1 = 50 cm = 0.5 m and f2 = 25 cm = 0.25 m. Both are convex lenses, so focal lengths are positive.
\nPower of the first lens: P1 = 1 \/ f1 = 1 \/ 0.5 m = +2 Dioptre (D).
\nPower of the second lens: P2 = 1 \/ f2 = 1 \/ 0.25 m = +4 Dioptre (D).
\nNet power of the combination: P_net = P1 + P2 = +2 D + +4 D = +6 D.<\/section>\n
The power of a lens is a measure of its ability to converge or diverge light, and for lenses in contact, powers are additive.<\/section>\n
The unit of power is the Dioptre (D), defined as the reciprocal of the focal length in meters. Convex lenses have positive power (converging), and concave lenses have negative power (diverging).<\/section>\n","protected":false},"excerpt":{"rendered":"

Two convex lenses have focal lengths of 50 cm and 25 cm, respectively. If these two lenses are placed in contact, then the net power of this combination will be equal to [amp_mcq option1=”+2 dioptre” option2=”+6 dioptre” option3=”-6 dioptre” option4=”+3 dioptre” correct=”option2″] This question was previously asked in UPSC NDA-2 – 2022 Download PDFAttempt Online … <\/p>\n

Detailed SolutionTwo convex lenses have focal lengths of 50 cm and 25 cm, respectively.<\/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":[1108,1153,1128],"class_list":["post-88901","post","type-post","status-publish","format-standard","hentry","category-upsc-nda-2","tag-1108","tag-optics","tag-physics","no-featured-image-padding"],"yoast_head":"\nTwo convex lenses have focal lengths of 50 cm and 25 cm, respectively.<\/title>\n<meta name=\"description\" content=\"The power of a lens (P) is the reciprocal of its focal length (f) in meters (P = 1\/f). For a combination of thin lenses in contact, the total power (P_net) is the sum of the individual powers (P_net = P1 + P2 + ...). Given focal lengths: f1 = 50 cm = 0.5 m and f2 = 25 cm = 0.25 m. Both are convex lenses, so focal lengths are positive. Power of the first lens: P1 = 1 \/ f1 = 1 \/ 0.5 m = +2 Dioptre (D). Power of the second lens: P2 = 1 \/ f2 = 1 \/ 0.25 m = +4 Dioptre (D). Net power of the combination: P_net = P1 + P2 = +2 D + +4 D = +6 D. The power of a lens is a measure of its ability to converge or diverge light, and for lenses in contact, powers are additive.\" \/>\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\/two-convex-lenses-have-focal-lengths-of-50-cm-and-25-cm-respectively\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Two convex lenses have focal lengths of 50 cm and 25 cm, respectively.\" \/>\n<meta property=\"og:description\" content=\"The power of a lens (P) is the reciprocal of its focal length (f) in meters (P = 1\/f). For a combination of thin lenses in contact, the total power (P_net) is the sum of the individual powers (P_net = P1 + P2 + ...). Given focal lengths: f1 = 50 cm = 0.5 m and f2 = 25 cm = 0.25 m. Both are convex lenses, so focal lengths are positive. Power of the first lens: P1 = 1 \/ f1 = 1 \/ 0.5 m = +2 Dioptre (D). Power of the second lens: P2 = 1 \/ f2 = 1 \/ 0.25 m = +4 Dioptre (D). Net power of the combination: P_net = P1 + P2 = +2 D + +4 D = +6 D. The power of a lens is a measure of its ability to converge or diverge light, and for lenses in contact, powers are additive.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/two-convex-lenses-have-focal-lengths-of-50-cm-and-25-cm-respectively\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T07:24:27+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=\"1 minute\" \/>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"Two convex lenses have focal lengths of 50 cm and 25 cm, respectively.","description":"The power of a lens (P) is the reciprocal of its focal length (f) in meters (P = 1\/f). For a combination of thin lenses in contact, the total power (P_net) is the sum of the individual powers (P_net = P1 + P2 + ...). Given focal lengths: f1 = 50 cm = 0.5 m and f2 = 25 cm = 0.25 m. Both are convex lenses, so focal lengths are positive. Power of the first lens: P1 = 1 \/ f1 = 1 \/ 0.5 m = +2 Dioptre (D). Power of the second lens: P2 = 1 \/ f2 = 1 \/ 0.25 m = +4 Dioptre (D). Net power of the combination: P_net = P1 + P2 = +2 D + +4 D = +6 D. The power of a lens is a measure of its ability to converge or diverge light, and for lenses in contact, powers are additive.","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\/two-convex-lenses-have-focal-lengths-of-50-cm-and-25-cm-respectively\/","og_locale":"en_US","og_type":"article","og_title":"Two convex lenses have focal lengths of 50 cm and 25 cm, respectively.","og_description":"The power of a lens (P) is the reciprocal of its focal length (f) in meters (P = 1\/f). For a combination of thin lenses in contact, the total power (P_net) is the sum of the individual powers (P_net = P1 + P2 + ...). Given focal lengths: f1 = 50 cm = 0.5 m and f2 = 25 cm = 0.25 m. Both are convex lenses, so focal lengths are positive. Power of the first lens: P1 = 1 \/ f1 = 1 \/ 0.5 m = +2 Dioptre (D). Power of the second lens: P2 = 1 \/ f2 = 1 \/ 0.25 m = +4 Dioptre (D). Net power of the combination: P_net = P1 + P2 = +2 D + +4 D = +6 D. The power of a lens is a measure of its ability to converge or diverge light, and for lenses in contact, powers are additive.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/two-convex-lenses-have-focal-lengths-of-50-cm-and-25-cm-respectively\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T07:24:27+00:00","author":"rawan239","twitter_card":"summary_large_image","twitter_misc":{"Written by":"rawan239","Est. reading time":"1 minute"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/exam.pscnotes.com\/mcq\/two-convex-lenses-have-focal-lengths-of-50-cm-and-25-cm-respectively\/","url":"https:\/\/exam.pscnotes.com\/mcq\/two-convex-lenses-have-focal-lengths-of-50-cm-and-25-cm-respectively\/","name":"Two convex lenses have focal lengths of 50 cm and 25 cm, respectively.","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T07:24:27+00:00","dateModified":"2025-06-01T07:24:27+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"The power of a lens (P) is the reciprocal of its focal length (f) in meters (P = 1\/f). For a combination of thin lenses in contact, the total power (P_net) is the sum of the individual powers (P_net = P1 + P2 + ...). Given focal lengths: f1 = 50 cm = 0.5 m and f2 = 25 cm = 0.25 m. Both are convex lenses, so focal lengths are positive. Power of the first lens: P1 = 1 \/ f1 = 1 \/ 0.5 m = +2 Dioptre (D). Power of the second lens: P2 = 1 \/ f2 = 1 \/ 0.25 m = +4 Dioptre (D). Net power of the combination: P_net = P1 + P2 = +2 D + +4 D = +6 D. The power of a lens is a measure of its ability to converge or diverge light, and for lenses in contact, powers are additive.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/two-convex-lenses-have-focal-lengths-of-50-cm-and-25-cm-respectively\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/two-convex-lenses-have-focal-lengths-of-50-cm-and-25-cm-respectively\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/two-convex-lenses-have-focal-lengths-of-50-cm-and-25-cm-respectively\/#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":"Two convex lenses have focal lengths of 50 cm and 25 cm, respectively."}]},{"@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\/88901","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=88901"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/88901\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=88901"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=88901"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=88901"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}