{"id":20977,"date":"2025-06-14T21:16:14","date_gmt":"2025-06-14T21:16:14","guid":{"rendered":"https:\/\/gaviki.com\/blog\/?p=20977"},"modified":"2025-06-14T21:16:19","modified_gmt":"2025-06-14T21:16:19","slug":"if-the-incident-angle-is-less-than-the-the-critical-angle","status":"publish","type":"post","link":"https:\/\/gaviki.com\/blog\/if-the-incident-angle-is-less-than-the-the-critical-angle\/","title":{"rendered":"If the incident angle is less than the the critical angle"},"content":{"rendered":"\n<p>If the incident angle is less than the the critical angle, then you will have total internal reflection. <\/p>\n\n\n\n<p> True <\/p>\n\n\n\n<p> False<\/p>\n\n\n\n<p><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-cyan-blue-color\"><strong>The correct answer and explanation is:<\/strong><\/mark><\/p>\n\n\n\n<p><strong>Correct Answer: \u274c False<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Explanation (300 words):<\/h3>\n\n\n\n<p>The statement <strong>&#8220;If the incident angle is less than the critical angle, then you will have total internal reflection&#8221;<\/strong> is <strong>false<\/strong>.<\/p>\n\n\n\n<p><strong>Total internal reflection (TIR)<\/strong> occurs <strong>only<\/strong> when <strong>two conditions<\/strong> are met:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Light travels from a medium with a higher refractive index to one with a lower refractive index<\/strong> (e.g., from water to air or glass to air).<\/li>\n\n\n\n<li>The <strong>angle of incidence is greater than or equal to the critical angle<\/strong>.<\/li>\n<\/ol>\n\n\n\n<p>The <strong>critical angle<\/strong> is the minimum angle of incidence at which light, moving from a denser (higher refractive index) to a rarer (lower refractive index) medium, <strong>is completely reflected back into the denser medium<\/strong> rather than refracted out.<\/p>\n\n\n\n<p>If the **incident angle is *<em>less<\/em>* than the critical angle**, light will *<em>partially refract<\/em>* into the second medium and <strong>partially reflect<\/strong> back into the first. <strong>Only<\/strong> when the angle of incidence <strong>equals or exceeds<\/strong> the critical angle does <strong>total internal reflection<\/strong> occur \u2014 meaning <strong>no refraction<\/strong>, just reflection.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Example:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Suppose light travels from <strong>water<\/strong> (n \u2248 1.33) into <strong>air<\/strong> (n \u2248 1.00).<\/li>\n\n\n\n<li>The <strong>critical angle<\/strong> can be calculated using Snell\u2019s Law: $$<br>\\theta_c = \\sin^{-1} \\left( \\frac{n_2}{n_1} \\right) = \\sin^{-1} \\left( \\frac{1.00}{1.33} \\right) \\approx 48.75^\\circ<br>$$<\/li>\n\n\n\n<li>If the incident angle is:<\/li>\n\n\n\n<li><strong>30\u00b0<\/strong> (less than the critical angle): Light <strong>partially refracts<\/strong> into the air.<\/li>\n\n\n\n<li><strong>50\u00b0<\/strong> (greater than the critical angle): <strong>Total internal reflection<\/strong> occurs.<\/li>\n<\/ul>\n\n\n\n<p>Thus, <strong>TIR does not happen if the incident angle is less than the critical angle<\/strong>, making the original statement false.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>If the incident angle is less than the the critical angle, then you will have total internal reflection. True False The correct answer and explanation is: Correct Answer: \u274c False Explanation (300 words): The statement &#8220;If the incident angle is less than the critical angle, then you will have total internal reflection&#8221; is false. Total [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-20977","post","type-post","status-publish","format-standard","hentry","category-quiz-questions"],"_links":{"self":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/20977","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/comments?post=20977"}],"version-history":[{"count":1,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/20977\/revisions"}],"predecessor-version":[{"id":20978,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/20977\/revisions\/20978"}],"wp:attachment":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/media?parent=20977"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/categories?post=20977"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/tags?post=20977"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}