{"id":87678,"date":"2025-06-01T06:51:06","date_gmt":"2025-06-01T06:51:06","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=87678"},"modified":"2025-06-01T06:51:06","modified_gmt":"2025-06-01T06:51:06","slug":"the-focal-length-of-the-objective-lens-of-a-telescope-is-50-cm-if-the","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/the-focal-length-of-the-objective-lens-of-a-telescope-is-50-cm-if-the\/","title":{"rendered":"The focal length of the objective lens of a telescope is 50 cm. If the"},"content":{"rendered":"

The focal length of the objective lens of a telescope is 50 cm. If the magnification of the telescope is 25, then the focal length of the eye-piece is<\/p>\n

[amp_mcq option1=”12.5 cm” option2=”5 cm” option3=”2 cm” option4=”10 cm” correct=”option3″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC NDA-1 – 2019<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nThe focal length of the eye-piece is 2 cm.
\n<\/section>\n
\nFor a refracting telescope used in normal adjustment (final image at infinity), the angular magnification (M) is given by the ratio of the focal length of the objective lens (f_o) to the focal length of the eye-piece lens (f_e): M = f_o \/ f_e.
\nGiven f_o = 50 cm and M = 25.
\nWe can rearrange the formula to solve for f_e: f_e = f_o \/ M.
\nSubstituting the given values: f_e = 50 cm \/ 25 = 2 cm.
\n<\/section>\n
\nA telescope achieves magnification by using an objective lens with a long focal length and an eye-piece lens with a short focal length. The objective forms a real, inverted image of a distant object at its focal plane, and the eye-piece acts as a magnifying glass to view this intermediate image.
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

The focal length of the objective lens of a telescope is 50 cm. If the magnification of the telescope is 25, then the focal length of the eye-piece is [amp_mcq option1=”12.5 cm” option2=”5 cm” option3=”2 cm” option4=”10 cm” correct=”option3″] This question was previously asked in UPSC NDA-1 – 2019 Download PDFAttempt Online The focal length … <\/p>\n

Detailed SolutionThe focal length of the objective lens of a telescope is 50 cm. If the<\/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":[1119,1153,1128],"class_list":["post-87678","post","type-post","status-publish","format-standard","hentry","category-upsc-nda-1","tag-1119","tag-optics","tag-physics","no-featured-image-padding"],"yoast_head":"\nThe focal length of the objective lens of a telescope is 50 cm. If the<\/title>\n<meta name=\"description\" content=\"The focal length of the eye-piece is 2 cm. For a refracting telescope used in normal adjustment (final image at infinity), the angular magnification (M) is given by the ratio of the focal length of the objective lens (f_o) to the focal length of the eye-piece lens (f_e): M = f_o \/ f_e. Given f_o = 50 cm and M = 25. We can rearrange the formula to solve for f_e: f_e = f_o \/ M. Substituting the given values: f_e = 50 cm \/ 25 = 2 cm.\" \/>\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\/the-focal-length-of-the-objective-lens-of-a-telescope-is-50-cm-if-the\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"The focal length of the objective lens of a telescope is 50 cm. If the\" \/>\n<meta property=\"og:description\" content=\"The focal length of the eye-piece is 2 cm. For a refracting telescope used in normal adjustment (final image at infinity), the angular magnification (M) is given by the ratio of the focal length of the objective lens (f_o) to the focal length of the eye-piece lens (f_e): M = f_o \/ f_e. Given f_o = 50 cm and M = 25. We can rearrange the formula to solve for f_e: f_e = f_o \/ M. Substituting the given values: f_e = 50 cm \/ 25 = 2 cm.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/the-focal-length-of-the-objective-lens-of-a-telescope-is-50-cm-if-the\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T06:51:06+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":"The focal length of the objective lens of a telescope is 50 cm. If the","description":"The focal length of the eye-piece is 2 cm. For a refracting telescope used in normal adjustment (final image at infinity), the angular magnification (M) is given by the ratio of the focal length of the objective lens (f_o) to the focal length of the eye-piece lens (f_e): M = f_o \/ f_e. Given f_o = 50 cm and M = 25. We can rearrange the formula to solve for f_e: f_e = f_o \/ M. Substituting the given values: f_e = 50 cm \/ 25 = 2 cm.","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\/the-focal-length-of-the-objective-lens-of-a-telescope-is-50-cm-if-the\/","og_locale":"en_US","og_type":"article","og_title":"The focal length of the objective lens of a telescope is 50 cm. If the","og_description":"The focal length of the eye-piece is 2 cm. For a refracting telescope used in normal adjustment (final image at infinity), the angular magnification (M) is given by the ratio of the focal length of the objective lens (f_o) to the focal length of the eye-piece lens (f_e): M = f_o \/ f_e. Given f_o = 50 cm and M = 25. We can rearrange the formula to solve for f_e: f_e = f_o \/ M. Substituting the given values: f_e = 50 cm \/ 25 = 2 cm.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/the-focal-length-of-the-objective-lens-of-a-telescope-is-50-cm-if-the\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T06:51:06+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\/the-focal-length-of-the-objective-lens-of-a-telescope-is-50-cm-if-the\/","url":"https:\/\/exam.pscnotes.com\/mcq\/the-focal-length-of-the-objective-lens-of-a-telescope-is-50-cm-if-the\/","name":"The focal length of the objective lens of a telescope is 50 cm. 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