{"id":255217,"date":"2025-07-12T20:49:28","date_gmt":"2025-07-12T20:49:28","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=255217"},"modified":"2025-07-12T20:49:30","modified_gmt":"2025-07-12T20:49:30","slug":"a-60-watt-incandescent-light-bulb-is-left-on-for-5-hours","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/07\/12\/a-60-watt-incandescent-light-bulb-is-left-on-for-5-hours\/","title":{"rendered":"A 60 watt incandescent light bulb is left on for 5 hours"},"content":{"rendered":"\n<p>A 60 watt incandescent light bulb is left on for 5 hours. How many hours will it take for a 15 watt compact fluorescent bulb to consume the same amount of energy? <\/p>\n\n\n\n<p>a. 4 <\/p>\n\n\n\n<p>b. 12 <\/p>\n\n\n\n<p>c. 20<\/p>\n\n\n\n<p> d. 75<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-6-color\">The correct answer and explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p>To find how long it would take for the 15-watt compact fluorescent bulb to consume the same amount of energy as a 60-watt incandescent light bulb, we first need to calculate the energy consumed by the incandescent bulb.<\/p>\n\n\n\n<p>The energy consumed by a light bulb can be calculated using the formula: E=P\u00d7tE = P \\times t<\/p>\n\n\n\n<p>where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>EE is the energy in watt-hours (Wh),<\/li>\n\n\n\n<li>PP is the power in watts (W),<\/li>\n\n\n\n<li>tt is the time in hours (h).<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Step 1: Calculate energy used by the incandescent bulb.<\/h3>\n\n\n\n<p>The incandescent bulb is 60 watts, and it is left on for 5 hours. So, E=60\u2009W\u00d75\u2009h=300\u2009Wh.E = 60 \\, \\text{W} \\times 5 \\, \\text{h} = 300 \\, \\text{Wh}.<\/p>\n\n\n\n<p>This means the incandescent bulb uses 300 watt-hours of energy in 5 hours.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Step 2: Calculate how long it will take for the 15-watt compact fluorescent bulb to use 300 watt-hours.<\/h3>\n\n\n\n<p>Now, we need to calculate the time tt it would take for the 15-watt compact fluorescent bulb to consume 300 watt-hours of energy. Rearranging the energy formula: t=EPt = \\frac{E}{P}<\/p>\n\n\n\n<p>Substitute E=300\u2009WhE = 300 \\, \\text{Wh} and P=15\u2009WP = 15 \\, \\text{W}: t=300\u2009Wh15\u2009W=20\u2009hours.t = \\frac{300 \\, \\text{Wh}}{15 \\, \\text{W}} = 20 \\, \\text{hours}.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Conclusion:<\/h3>\n\n\n\n<p>It will take 20 hours for the 15-watt compact fluorescent bulb to consume the same amount of energy as the 60-watt incandescent bulb.<\/p>\n\n\n\n<p>So, the correct answer is <strong>c. 20 hours<\/strong>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A 60 watt incandescent light bulb is left on for 5 hours. How many hours will it take for a 15 watt compact fluorescent bulb to consume the same amount of energy? a. 4 b. 12 c. 20 d. 75 The correct answer and explanation is: To find how long it would take for 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-255217","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/255217","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=255217"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/255217\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=255217"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=255217"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=255217"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}