{"id":84983,"date":"2025-06-01T02:58:55","date_gmt":"2025-06-01T02:58:55","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=84983"},"modified":"2025-06-01T02:58:55","modified_gmt":"2025-06-01T02:58:55","slug":"if-the-speed-of-light-in-air-is-3-times-108-m-s-then-the-speed-of","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/if-the-speed-of-light-in-air-is-3-times-108-m-s-then-the-speed-of\/","title":{"rendered":"If the speed of light in air is $3 \\times 10^8$ m\/s, then the speed of"},"content":{"rendered":"

If the speed of light in air is $3 \\times 10^8$ m\/s, then the speed of light in a medium of refractive index $\\frac{3}{2}$ is<\/p>\n

[amp_mcq option1=”$2 \\times 10^8$ m\/s” option2=”$\\frac{9}{4} \\times 10^8$ m\/s” option3=”$\\frac{3}{2} \\times 10^8$ m\/s” option4=”$3 \\times 10^8$ m\/s” correct=”option1″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC CDS-1 – 2020<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nThe refractive index (n) of a medium is defined as the ratio of the speed of light in a vacuum (c) to the speed of light in that medium (v). The formula is $n = c\/v$. Given the speed of light in air (approximately equal to the speed in vacuum) $c = 3 \\times 10^8$ m\/s and the refractive index of the medium $n = 3\/2$, we can find the speed of light in the medium ($v$) by rearranging the formula: $v = c\/n$.
\n$v = (3 \\times 10^8 \\, \\text{m\/s}) \/ (3\/2) = (3 \\times 10^8 \\, \\text{m\/s}) \\times (2\/3) = 2 \\times 10^8$ m\/s.
\n<\/section>\n
\n– Refractive index $n = c\/v$.
\n– $c$ is the speed of light in vacuum (or air).
\n– $v$ is the speed of light in the medium.
\n<\/section>\n
\nThe refractive index is a dimensionless quantity and is always greater than or equal to 1. A higher refractive index indicates a slower speed of light in the medium. The speed of light is maximum in vacuum.
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

If the speed of light in air is $3 \\times 10^8$ m\/s, then the speed of light in a medium of refractive index $\\frac{3}{2}$ is [amp_mcq option1=”$2 \\times 10^8$ m\/s” option2=”$\\frac{9}{4} \\times 10^8$ m\/s” option3=”$\\frac{3}{2} \\times 10^8$ m\/s” option4=”$3 \\times 10^8$ m\/s” correct=”option1″] This question was previously asked in UPSC CDS-1 – 2020 Download PDFAttempt … <\/p>\n

Detailed SolutionIf the speed of light in air is $3 \\times 10^8$ m\/s, then the speed of<\/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":[1087],"tags":[1288,1153,1128],"class_list":["post-84983","post","type-post","status-publish","format-standard","hentry","category-upsc-cds-1","tag-1288","tag-optics","tag-physics","no-featured-image-padding"],"yoast_head":"\nIf the speed of light in air is $3 \\times 10^8$ m\/s, then the speed of<\/title>\n<meta name=\"description\" content=\"The refractive index (n) of a medium is defined as the ratio of the speed of light in a vacuum (c) to the speed of light in that medium (v). The formula is $n = c\/v$. Given the speed of light in air (approximately equal to the speed in vacuum) $c = 3 times 10^8$ m\/s and the refractive index of the medium $n = 3\/2$, we can find the speed of light in the medium ($v$) by rearranging the formula: $v = c\/n$. $v = (3 times 10^8 , text{m\/s}) \/ (3\/2) = (3 times 10^8 , text{m\/s}) times (2\/3) = 2 times 10^8$ m\/s. - Refractive index $n = c\/v$. - $c$ is the speed of light in vacuum (or air). - $v$ is the speed of light in the medium.\" \/>\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\/if-the-speed-of-light-in-air-is-3-times-108-m-s-then-the-speed-of\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"If the speed of light in air is $3 \\times 10^8$ m\/s, then the speed of\" \/>\n<meta property=\"og:description\" content=\"The refractive index (n) of a medium is defined as the ratio of the speed of light in a vacuum (c) to the speed of light in that medium (v). The formula is $n = c\/v$. Given the speed of light in air (approximately equal to the speed in vacuum) $c = 3 times 10^8$ m\/s and the refractive index of the medium $n = 3\/2$, we can find the speed of light in the medium ($v$) by rearranging the formula: $v = c\/n$. $v = (3 times 10^8 , text{m\/s}) \/ (3\/2) = (3 times 10^8 , text{m\/s}) times (2\/3) = 2 times 10^8$ m\/s. - Refractive index $n = c\/v$. - $c$ is the speed of light in vacuum (or air). - $v$ is the speed of light in the medium.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/if-the-speed-of-light-in-air-is-3-times-108-m-s-then-the-speed-of\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T02:58:55+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":"If the speed of light in air is $3 \\times 10^8$ m\/s, then the speed of","description":"The refractive index (n) of a medium is defined as the ratio of the speed of light in a vacuum (c) to the speed of light in that medium (v). The formula is $n = c\/v$. Given the speed of light in air (approximately equal to the speed in vacuum) $c = 3 times 10^8$ m\/s and the refractive index of the medium $n = 3\/2$, we can find the speed of light in the medium ($v$) by rearranging the formula: $v = c\/n$. $v = (3 times 10^8 , text{m\/s}) \/ (3\/2) = (3 times 10^8 , text{m\/s}) times (2\/3) = 2 times 10^8$ m\/s. - Refractive index $n = c\/v$. - $c$ is the speed of light in vacuum (or air). - $v$ is the speed of light in the medium.","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\/if-the-speed-of-light-in-air-is-3-times-108-m-s-then-the-speed-of\/","og_locale":"en_US","og_type":"article","og_title":"If the speed of light in air is $3 \\times 10^8$ m\/s, then the speed of","og_description":"The refractive index (n) of a medium is defined as the ratio of the speed of light in a vacuum (c) to the speed of light in that medium (v). The formula is $n = c\/v$. Given the speed of light in air (approximately equal to the speed in vacuum) $c = 3 times 10^8$ m\/s and the refractive index of the medium $n = 3\/2$, we can find the speed of light in the medium ($v$) by rearranging the formula: $v = c\/n$. $v = (3 times 10^8 , text{m\/s}) \/ (3\/2) = (3 times 10^8 , text{m\/s}) times (2\/3) = 2 times 10^8$ m\/s. - Refractive index $n = c\/v$. - $c$ is the speed of light in vacuum (or air). - $v$ is the speed of light in the medium.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/if-the-speed-of-light-in-air-is-3-times-108-m-s-then-the-speed-of\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T02:58:55+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\/if-the-speed-of-light-in-air-is-3-times-108-m-s-then-the-speed-of\/","url":"https:\/\/exam.pscnotes.com\/mcq\/if-the-speed-of-light-in-air-is-3-times-108-m-s-then-the-speed-of\/","name":"If the speed of light in air is $3 \\times 10^8$ m\/s, then the speed of","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T02:58:55+00:00","dateModified":"2025-06-01T02:58:55+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"The refractive index (n) of a medium is defined as the ratio of the speed of light in a vacuum (c) to the speed of light in that medium (v). 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Given the speed of light in air (approximately equal to the speed in vacuum) $c = 3 \\times 10^8$ m\/s and the refractive index of the medium $n = 3\/2$, we can find the speed of light in the medium ($v$) by rearranging the formula: $v = c\/n$. $v = (3 \\times 10^8 \\, \\text{m\/s}) \/ (3\/2) = (3 \\times 10^8 \\, \\text{m\/s}) \\times (2\/3) = 2 \\times 10^8$ m\/s. - Refractive index $n = c\/v$. - $c$ is the speed of light in vacuum (or air). - $v$ is the speed of light in the medium.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/if-the-speed-of-light-in-air-is-3-times-108-m-s-then-the-speed-of\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/if-the-speed-of-light-in-air-is-3-times-108-m-s-then-the-speed-of\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/if-the-speed-of-light-in-air-is-3-times-108-m-s-then-the-speed-of\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/exam.pscnotes.com\/mcq\/"},{"@type":"ListItem","position":2,"name":"UPSC CDS-1","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/upsc-cds-1\/"},{"@type":"ListItem","position":3,"name":"If the speed of light in air is $3 \\times 10^8$ m\/s, then the speed of"}]},{"@type":"WebSite","@id":"https:\/\/exam.pscnotes.com\/mcq\/#website","url":"https:\/\/exam.pscnotes.com\/mcq\/","name":"MCQ and Quiz for Exams","description":"","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/exam.pscnotes.com\/mcq\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209","name":"rawan239","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/image\/","url":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","caption":"rawan239"},"sameAs":["https:\/\/exam.pscnotes.com"],"url":"https:\/\/exam.pscnotes.com\/mcq\/author\/rawan239\/"}]}},"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/84983","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/comments?post=84983"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/84983\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=84983"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=84983"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=84983"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}