{"id":90014,"date":"2025-06-01T10:19:09","date_gmt":"2025-06-01T10:19:09","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=90014"},"modified":"2025-06-01T10:19:09","modified_gmt":"2025-06-01T10:19:09","slug":"there-are-two-concentric-circles-the-radii-of-the-two-circles-are-100","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/there-are-two-concentric-circles-the-radii-of-the-two-circles-are-100\/","title":{"rendered":"There are two concentric circles. The radii of the two circles are 100"},"content":{"rendered":"<p>There are two concentric circles. The radii of the two circles are 100 m and 110 m respectively. A wheel of radius 30 cm rolls on the smaller circle and another wheel rolls on the larger circle. After they have completed one revolution, it is found that the two wheels rolled equal number of times on their respective axes. What is the radius of the other wheel ?<\/p>\n<p>[amp_mcq option1=&#8221;31 cm&#8221; option2=&#8221;32 cm&#8221; option3=&#8221;33 cm&#8221; option4=&#8221;34 cm&#8221; correct=&#8221;option3&#8243;]<\/p>\n<div class=\"psc-box-pyq-exam-year-detail\">\n<div class=\"pyq-exam\">\n<div class=\"psc-heading\">This question was previously asked in<\/div>\n<div class=\"psc-title line-ellipsis\">UPSC CAPF &#8211; 2016<\/div>\n<\/div>\n<div class=\"pyq-exam-psc-buttons\"><a href=\"\/pyq\/pyq-upsc-capf-2016.pdf\" target=\"_blank\" class=\"psc-pdf-button\" rel=\"noopener\">Download PDF<\/a><a href=\"\/pyq-upsc-capf-2016\" target=\"_blank\" class=\"psc-attempt-button\" rel=\"noopener\">Attempt Online<\/a><\/div>\n<\/div>\n<section id=\"pyq-correct-answer\">\nThe correct option is C) 33 cm.<br \/>\n<\/section>\n<section id=\"pyq-key-points\">\nWhen a wheel rolls on the circumference of a circle, the distance covered by the wheel&#8217;s point of contact is equal to the circumference of the larger circle it&#8217;s rolling on. This distance is also equal to the number of revolutions the wheel makes on its own axis multiplied by its own circumference.<br \/>\n<\/section>\n<section id=\"pyq-additional-information\">\nRadius of the smaller circle (R1) = 100 m = 10000 cm.<br \/>\nRadius of the larger circle (R2) = 110 m = 11000 cm.<br \/>\nRadius of the first wheel (r1) = 30 cm.<br \/>\nLet N be the number of revolutions made by each wheel on its axis.<br \/>\nThe first wheel rolls on the smaller circle (R1). The distance covered by its point of contact is the circumference of the smaller circle, which is 2\u03c0R1. This distance is also equal to N times the circumference of the first wheel, which is N * 2\u03c0r1.<br \/>\nSo, 2\u03c0R1 = N * 2\u03c0r1<br \/>\nR1 = N * r1<br \/>\n10000 = N * 30<br \/>\nN = 10000 \/ 30 = 1000 \/ 3<\/p>\n<p>The second wheel rolls on the larger circle (R2). Let its radius be r2. The distance covered by its point of contact is the circumference of the larger circle, which is 2\u03c0R2. This distance is also equal to N times the circumference of the second wheel, which is N * 2\u03c0r2.<br \/>\nSo, 2\u03c0R2 = N * 2\u03c0r2<br \/>\nR2 = N * r2<\/p>\n<p>We know R2 = 11000 cm and N = 1000\/3.<br \/>\n11000 = (1000\/3) * r2<br \/>\nr2 = 11000 * (3 \/ 1000)<br \/>\nr2 = 11 * 3 = 33 cm.<\/p>\n<p>The radius of the other wheel is 33 cm.<br \/>\n<\/section>\n","protected":false},"excerpt":{"rendered":"<p>There are two concentric circles. The radii of the two circles are 100 m and 110 m respectively. A wheel of radius 30 cm rolls on the smaller circle and another wheel rolls on the larger circle. After they have completed one revolution, it is found that the two wheels rolled equal number of times &#8230; <\/p>\n<p class=\"read-more-container\"><a title=\"There are two concentric circles. The radii of the two circles are 100\" class=\"read-more button\" href=\"https:\/\/exam.pscnotes.com\/mcq\/there-are-two-concentric-circles-the-radii-of-the-two-circles-are-100\/#more-90014\">Detailed Solution<span class=\"screen-reader-text\">There are two concentric circles. The radii of the two circles are 100<\/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":[1085],"tags":[1098,1102],"class_list":["post-90014","post","type-post","status-publish","format-standard","hentry","category-upsc-capf","tag-1098","tag-quantitative-aptitude-and-reasoning","no-featured-image-padding"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v22.2 (Yoast SEO v23.3) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>There are two concentric circles. The radii of the two circles are 100<\/title>\n<meta name=\"description\" content=\"The correct option is C) 33 cm. When a wheel rolls on the circumference of a circle, the distance covered by the wheel&#039;s point of contact is equal to the circumference of the larger circle it&#039;s rolling on. This distance is also equal to the number of revolutions the wheel makes on its own axis multiplied by its own circumference.\" \/>\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\/there-are-two-concentric-circles-the-radii-of-the-two-circles-are-100\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"There are two concentric circles. The radii of the two circles are 100\" \/>\n<meta property=\"og:description\" content=\"The correct option is C) 33 cm. When a wheel rolls on the circumference of a circle, the distance covered by the wheel&#039;s point of contact is equal to the circumference of the larger circle it&#039;s rolling on. This distance is also equal to the number of revolutions the wheel makes on its own axis multiplied by its own circumference.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/there-are-two-concentric-circles-the-radii-of-the-two-circles-are-100\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T10:19:09+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":"There are two concentric circles. The radii of the two circles are 100","description":"The correct option is C) 33 cm. When a wheel rolls on the circumference of a circle, the distance covered by the wheel's point of contact is equal to the circumference of the larger circle it's rolling on. This distance is also equal to the number of revolutions the wheel makes on its own axis multiplied by its own circumference.","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\/there-are-two-concentric-circles-the-radii-of-the-two-circles-are-100\/","og_locale":"en_US","og_type":"article","og_title":"There are two concentric circles. The radii of the two circles are 100","og_description":"The correct option is C) 33 cm. When a wheel rolls on the circumference of a circle, the distance covered by the wheel's point of contact is equal to the circumference of the larger circle it's rolling on. This distance is also equal to the number of revolutions the wheel makes on its own axis multiplied by its own circumference.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/there-are-two-concentric-circles-the-radii-of-the-two-circles-are-100\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T10:19:09+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\/there-are-two-concentric-circles-the-radii-of-the-two-circles-are-100\/","url":"https:\/\/exam.pscnotes.com\/mcq\/there-are-two-concentric-circles-the-radii-of-the-two-circles-are-100\/","name":"There are two concentric circles. 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This distance is also equal to the number of revolutions the wheel makes on its own axis multiplied by its own circumference.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/there-are-two-concentric-circles-the-radii-of-the-two-circles-are-100\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/there-are-two-concentric-circles-the-radii-of-the-two-circles-are-100\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/there-are-two-concentric-circles-the-radii-of-the-two-circles-are-100\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/exam.pscnotes.com\/mcq\/"},{"@type":"ListItem","position":2,"name":"UPSC CAPF","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/upsc-capf\/"},{"@type":"ListItem","position":3,"name":"There are two concentric circles. 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