{"id":29378,"date":"2024-02-23T10:04:39","date_gmt":"2024-02-23T10:04:39","guid":{"rendered":"https:\/\/edukemy.com\/blog\/?p=29378"},"modified":"2024-02-23T10:04:41","modified_gmt":"2024-02-23T10:04:41","slug":"upsc-prelims-2021-question-2","status":"publish","type":"post","link":"https:\/\/edukemy.com\/blog\/upsc-prelims-2021-question-2\/","title":{"rendered":"UPSC Prelims 2021 &#8211; Question 2"},"content":{"rendered":"\n<figure class=\"wp-block-image size-full is-resized\"><a href=\"https:\/\/edukemy.com\/upsc\/upsc-prelims-test-series?utm_source=Blog&amp;utm_medium=Blog&amp;utm_campaign=Blog-%20PTS\" target=\"_blank\" rel=\"noreferrer noopener\"><img fetchpriority=\"high\" decoding=\"async\" src=\"https:\/\/edukemy.com\/blog\/wp-content\/uploads\/2024\/02\/Prelims-Test-Series-eng-and-hindi-1280\u00d7330.svg\" alt=\"UPSC Prelims Mock Test - ECONOMY 2\" class=\"wp-image-24924\" width=\"779\" height=\"199\"\/><\/a><\/figure>\n\n\n\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_73 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<label for=\"ez-toc-cssicon-toggle-item-69f5065c7dc28\" class=\"ez-toc-cssicon-toggle-label\"><p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-cssicon\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/label><input type=\"checkbox\"  id=\"ez-toc-cssicon-toggle-item-69f5065c7dc28\"  \/><nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/edukemy.com\/blog\/upsc-prelims-2021-question-2\/#Q2_With_reference_to_street_lighting_how_do_sodium_lamps_differ_from_LED_lamps\" title=\"Q2. With reference to street lighting, how do sodium lamps differ from LED lamps?\">Q2. With reference to street lighting, how do sodium lamps differ from LED lamps?<\/a><\/li><\/ul><\/nav><\/div>\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Q2_With_reference_to_street_lighting_how_do_sodium_lamps_differ_from_LED_lamps\"><\/span>Q2. With reference to street lighting, how do sodium lamps differ from LED lamps?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<ol class=\"wp-block-list\"><li>Sodium lamps produce light in 360 degrees but it is not so in the case of LED lamps.<\/li><li>As street lights, sodium lamps have a longer life span than LED lamps.<\/li><li>The spectrum of visible light from sodium lamps is almost monochromatic while LED lamps offer significant color advantages in street lighting.<\/li><\/ol>\n\n\n\n<p>Select the correct answer using the code given below.<br>a) 3 only<br>b) 2 only<br>c) 1 and 3 only<br>d) 1, 2 and 3<\/p>\n\n\n\n<p>Answer: (c) <\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>The first statement is true. Sodium lamps emit light in all directions, whereas LED bulbs do not. The 180-degree bulb angle of LED lamps maintains light efficiency and enables area-target lighting.<\/li><li>The second claim is untrue. As street lights, sodium lamps typically last less time than LED bulbs. High-pressure sodium lamps typically last for 24,000 hours on average. While the lifespan of an LED lamp is between 25,000 and 200,000 hours.<\/li><li>The third statement is true. Due to their well-known warm yellow glow, sodium lamps provide almost monochromatic visible light. However, when it comes to street lighting, LED bulbs have substantial color advantages. Better illumination options are provided by LEDs\u2019 range of color possibilities.<\/li><\/ul>\n\n\n\n<figure class=\"wp-block-image size-full is-resized\"><a href=\"https:\/\/edukemy.com\/upsc\/upsc-essay?utm_source=Blog&amp;utm_medium=Banner&amp;utm_campaign=Essay\" target=\"_blank\" rel=\"noreferrer noopener\"><img decoding=\"async\" data-src=\"https:\/\/edukemy.com\/blog\/wp-content\/uploads\/2024\/06\/UPSC-Essay-Course-1280\u00d7300-1-3.svg\" alt=\"\" class=\"wp-image-42688 lazyload\" width=\"781\" height=\"182\" src=\"data:image\/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==\" style=\"--smush-placeholder-width: 781px; --smush-placeholder-aspect-ratio: 781\/182;\" \/><\/a><\/figure>\n\n\n\n<p>For UPSC Prelims Resources,&nbsp;<a href=\"https:\/\/edukemy.com\/upsc-cse-prelims-resource-centre\" target=\"_blank\" rel=\"noreferrer noopener\">Click here<\/a><\/p>\n\n\n\n<p>For Daily Updates and Study Material:<\/p>\n\n\n\n<p>Join our Telegram Channel \u2013&nbsp;<a href=\"https:\/\/t.me\/WithEdukemy4IAS\" target=\"_blank\" rel=\"noreferrer noopener\">Edukemy for IAS<\/a><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>1. Learn through Videos \u2013&nbsp;<a href=\"https:\/\/bit.ly\/3vOD8sU\" target=\"_blank\" rel=\"noreferrer noopener\">here<\/a><\/li><li>2. Be Exam Ready by Practicing Daily MCQs \u2013&nbsp;<a href=\"https:\/\/bit.ly\/3Q9z2nF\" target=\"_blank\" rel=\"noreferrer noopener\">here<\/a><\/li><li>3. Daily Newsletter \u2013 Get all your Current Affairs Covered \u2013&nbsp;<a href=\"https:\/\/bit.ly\/3bE2y5J\" target=\"_blank\" rel=\"noreferrer noopener\">here<\/a><\/li><li>4. Mains Answer Writing Practice \u2013&nbsp;<a href=\"https:\/\/bit.ly\/3mZuVxl\" target=\"_blank\" rel=\"noreferrer noopener\">here<\/a><\/li><\/ul>\n\n\n\n<p>Visit our YouTube Channel \u2013&nbsp;<a href=\"https:\/\/www.youtube.com\/@ShabbirsEduKemyforIAS\" target=\"_blank\" rel=\"noreferrer noopener\">here<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Q2. With reference to street lighting, how do sodium lamps differ from LED lamps?<\/p>\n<p>Sodium lamps produce light in 360 degrees but it is not so in the case<\/p>\n","protected":false},"author":17,"featured_media":29382,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_eb_attr":"","om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_uf_show_specific_survey":0,"_uf_disable_surveys":false,"_lmt_disableupdate":"","_lmt_disable":"","footnotes":""},"categories":[1643],"tags":[232,515,230],"class_list":["post-29378","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-upsc-mains","tag-upsc","tag-upsc-cse","tag-upsc-mains"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/edukemy.com\/blog\/wp-json\/wp\/v2\/posts\/29378","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/edukemy.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/edukemy.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/edukemy.com\/blog\/wp-json\/wp\/v2\/users\/17"}],"replies":[{"embeddable":true,"href":"https:\/\/edukemy.com\/blog\/wp-json\/wp\/v2\/comments?post=29378"}],"version-history":[{"count":1,"href":"https:\/\/edukemy.com\/blog\/wp-json\/wp\/v2\/posts\/29378\/revisions"}],"predecessor-version":[{"id":29383,"href":"https:\/\/edukemy.com\/blog\/wp-json\/wp\/v2\/posts\/29378\/revisions\/29383"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/edukemy.com\/blog\/wp-json\/wp\/v2\/media\/29382"}],"wp:attachment":[{"href":"https:\/\/edukemy.com\/blog\/wp-json\/wp\/v2\/media?parent=29378"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/edukemy.com\/blog\/wp-json\/wp\/v2\/categories?post=29378"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/edukemy.com\/blog\/wp-json\/wp\/v2\/tags?post=29378"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}