{"id":37272,"date":"2025-06-25T14:41:40","date_gmt":"2025-06-25T14:41:40","guid":{"rendered":"https:\/\/gaviki.com\/blog\/?p=37272"},"modified":"2025-06-25T14:41:42","modified_gmt":"2025-06-25T14:41:42","slug":"iodine-131-has-a-short-half-life-of-8-14-days","status":"publish","type":"post","link":"https:\/\/gaviki.com\/blog\/iodine-131-has-a-short-half-life-of-8-14-days\/","title":{"rendered":"Iodine-131 has a short half-life of 8.14 days"},"content":{"rendered":"\n<p>Iodine-131 has a short half-life of 8.14 days. Suppose the initial amount of Iodine-131 is 50 grams. How much of the initial amount of 50 grams will be radioactive after 30 days?<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-cyan-blue-color\">The correct answer and explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p>To find the amount of Iodine-131 remaining after 30 days, we use the radioactive decay formula:<\/p>\n\n\n\n<p><strong>A(t) = A\u2080 \u00d7 (1\/2)^(t \/ T)<\/strong><\/p>\n\n\n\n<p>Where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>A(t)<\/strong> is the amount remaining after time <strong>t<\/strong><\/li>\n\n\n\n<li><strong>A\u2080<\/strong> is the initial amount<\/li>\n\n\n\n<li><strong>T<\/strong> is the half-life<\/li>\n\n\n\n<li><strong>t<\/strong> is the elapsed time<\/li>\n<\/ul>\n\n\n\n<p><strong>Given:<\/strong><br>A\u2080 = 50 grams<br>T = 8.14 days<br>t = 30 days<\/p>\n\n\n\n<p><strong>Step 1: Plug the values into the formula<\/strong><br>A(30) = 50 \u00d7 (1\/2)^(30 \/ 8.14)<\/p>\n\n\n\n<p><strong>Step 2: Calculate the exponent<\/strong><br>30 \u00f7 8.14 \u2248 3.686<\/p>\n\n\n\n<p><strong>Step 3: Calculate (1\/2)^3.686<\/strong><br>(1\/2)^3.686 \u2248 0.0786<\/p>\n\n\n\n<p><strong>Step 4: Multiply by the initial amount<\/strong><br>A(30) = 50 \u00d7 0.0786 \u2248 <strong>3.93 grams<\/strong><\/p>\n\n\n\n<p><strong>Correct Answer:<\/strong><br>Approximately <strong>3.93 grams<\/strong> of the original 50 grams of Iodine-131 will remain radioactive after 30 days.<\/p>\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>Radioactive isotopes like Iodine-131 decay over time following an exponential pattern. The rate of decay is characterized by the half-life, which is the time it takes for half of a substance to decay. In this case, the half-life is 8.14 days, which means that every 8.14 days, the amount of Iodine-131 is halved.<\/p>\n\n\n\n<p>After one half-life, 25 grams would remain. After two, 12.5 grams. However, 30 days is not a perfect multiple of the half-life, so the decay must be calculated using the exponential formula. This approach gives a more accurate result than repeated halving, especially for times that are not exact multiples of the half-life.<\/p>\n\n\n\n<p>This exponential decay ensures that the substance never truly reaches zero but becomes negligible after several half-lives. Iodine-131&#8217;s rapid decay is useful in medical applications, especially in treatments where short-term radiation is beneficial.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Iodine-131 has a short half-life of 8.14 days. Suppose the initial amount of Iodine-131 is 50 grams. How much of the initial amount of 50 grams will be radioactive after 30 days? The correct answer and explanation is: To find the amount of Iodine-131 remaining after 30 days, we use the radioactive decay formula: A(t) [&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-37272","post","type-post","status-publish","format-standard","hentry","category-quiz-questions"],"_links":{"self":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/37272","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=37272"}],"version-history":[{"count":1,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/37272\/revisions"}],"predecessor-version":[{"id":37273,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/37272\/revisions\/37273"}],"wp:attachment":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/media?parent=37272"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/categories?post=37272"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/tags?post=37272"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}