{"id":230160,"date":"2025-06-09T04:33:22","date_gmt":"2025-06-09T04:33:22","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=230160"},"modified":"2025-06-09T04:33:24","modified_gmt":"2025-06-09T04:33:24","slug":"in-a-sorvall-t-865-fixed-angle-rotor-the-distance-to-the-axis-of-rotation-is-3-84-cm-at-the-top-of-the-tube-and-9-10-cm-at-the-bottom-of-the-tube","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/09\/in-a-sorvall-t-865-fixed-angle-rotor-the-distance-to-the-axis-of-rotation-is-3-84-cm-at-the-top-of-the-tube-and-9-10-cm-at-the-bottom-of-the-tube\/","title":{"rendered":"In a Sorvall T-865 fixed-angle rotor, the distance to the axis of rotation is 3.84 cm at the top of the tube and 9.10 cm at the bottom of the tube."},"content":{"rendered":"\n<p>In a Sorvall T-865 fixed-angle rotor, the distance to the axis of rotation is 3.84 cm at the top of the tube and 9.10 cm at the bottom of the tube. Calculate the RCF at 20,000 rpm at the top and the bottom of the tube.<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-1-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p>To calculate the <strong>relative centrifugal force (RCF)<\/strong> at different positions in a centrifuge tube, we use the formula:RCF=1.118\u00d710\u22125\u00d7r\u00d7(RPM)2\\text{RCF} = 1.118 \\times 10^{-5} \\times r \\times (\\text{RPM})^2RCF=1.118\u00d710\u22125\u00d7r\u00d7(RPM)2<\/p>\n\n\n\n<p>Where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>RCF\\text{RCF}RCF is in units of <em>g<\/em> (gravitational force),<\/li>\n\n\n\n<li>rrr is the <strong>radius<\/strong> or distance from the axis of rotation (in <strong>cm<\/strong>),<\/li>\n\n\n\n<li>RPM\\text{RPM}RPM is the <strong>rotational speed<\/strong> (in revolutions per minute).<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Given:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>RPM = 20,000<\/li>\n\n\n\n<li>rtop=3.84\u2009cmr_{\\text{top}} = 3.84 \\, \\text{cm}rtop\u200b=3.84cm<\/li>\n\n\n\n<li>rbottom=9.10\u2009cmr_{\\text{bottom}} = 9.10 \\, \\text{cm}rbottom\u200b=9.10cm<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Step 1: Calculate RCF at the <strong>top<\/strong> of the tube<\/h3>\n\n\n\n<p>RCFtop=1.118\u00d710\u22125\u00d73.84\u00d7(20000)2\\text{RCF}_{\\text{top}} = 1.118 \\times 10^{-5} \\times 3.84 \\times (20000)^2RCFtop\u200b=1.118\u00d710\u22125\u00d73.84\u00d7(20000)2RCFtop=1.118\u00d710\u22125\u00d73.84\u00d7400,000,000\\text{RCF}_{\\text{top}} = 1.118 \\times 10^{-5} \\times 3.84 \\times 400,000,000RCFtop\u200b=1.118\u00d710\u22125\u00d73.84\u00d7400,000,000RCFtop\u22481.118\u00d73.84\u00d74000\u224817151.55\u2009g\\text{RCF}_{\\text{top}} \\approx 1.118 \\times 3.84 \\times 4000 \\approx 17151.55 \\, gRCFtop\u200b\u22481.118\u00d73.84\u00d74000\u224817151.55g<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Step 2: Calculate RCF at the <strong>bottom<\/strong> of the tube<\/h3>\n\n\n\n<p>RCFbottom=1.118\u00d710\u22125\u00d79.10\u00d7(20000)2\\text{RCF}_{\\text{bottom}} = 1.118 \\times 10^{-5} \\times 9.10 \\times (20000)^2RCFbottom\u200b=1.118\u00d710\u22125\u00d79.10\u00d7(20000)2RCFbottom=1.118\u00d710\u22125\u00d79.10\u00d7400,000,000\\text{RCF}_{\\text{bottom}} = 1.118 \\times 10^{-5} \\times 9.10 \\times 400,000,000RCFbottom\u200b=1.118\u00d710\u22125\u00d79.10\u00d7400,000,000RCFbottom\u22481.118\u00d79.10\u00d74000\u224840788.88\u2009g\\text{RCF}_{\\text{bottom}} \\approx 1.118 \\times 9.10 \\times 4000 \\approx 40788.88 \\, gRCFbottom\u200b\u22481.118\u00d79.10\u00d74000\u224840788.88g<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Final Answers:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>RCF at the top<\/strong> of the tube \u2248 <strong>17,152 g<\/strong><\/li>\n\n\n\n<li><strong>RCF at the bottom<\/strong> of the tube \u2248 <strong>40,789 g<\/strong><\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Explanation<\/h3>\n\n\n\n<p>In centrifugation, Relative Centrifugal Force (RCF) is the force exerted on particles during spinning, expressed as a multiple of Earth&#8217;s gravitational force (g). It\u2019s a critical factor for efficient separation of components in biological or chemical samples. RCF depends on both the rotational speed (RPM) and the distance from the axis of rotation (radius, r). The farther a sample is from the center, the greater the force it experiences.<\/p>\n\n\n\n<p>This calculation uses a Sorvall T-865 fixed-angle rotor, where the tubes are held at an angle, so different parts of the sample sit at different radii. In this case, the sample spans from 3.84 cm (top) to 9.10 cm (bottom) from the axis. When spinning at 20,000 rpm, particles at the bottom of the tube experience significantly more force than those at the top because RCF is directly proportional to the radius.<\/p>\n\n\n\n<p>This difference in RCF within a single tube explains why particles sediment toward the bottom during centrifugation. It also highlights the importance of specifying <strong>RCF instead of RPM<\/strong> in protocols, because the same RPM produces different forces in different rotors or even different positions within a rotor.<\/p>\n\n\n\n<p>The calculations show that RCF increases from about <strong>17,152 g<\/strong> at the top to <strong>40,789 g<\/strong> at the bottom of the tube. This range is crucial for separating particles based on density and size. For precise lab work, particularly in molecular biology or clinical diagnostics, knowing the exact RCF ensures reproducibility and efficiency of separations.<\/p>\n\n\n\n<p>Hence, understanding and calculating RCF at different positions within a centrifuge tube is essential for correct interpretation and application of centrifugation results.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/learnexams.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner5-172.jpeg\" alt=\"\" class=\"wp-image-230161\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>In a Sorvall T-865 fixed-angle rotor, the distance to the axis of rotation is 3.84 cm at the top of the tube and 9.10 cm at the bottom of the tube. Calculate the RCF at 20,000 rpm at the top and the bottom of the tube. The Correct Answer and Explanation is: To calculate the [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-230160","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/230160","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=230160"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/230160\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=230160"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=230160"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=230160"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}