<?xml version="1.0" encoding="UTF-8" ?><!-- generator=Zoho Sites --><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:content="http://purl.org/rss/1.0/modules/content/"><channel><atom:link href="https://www.physicshelpline.com/Question/modern-physics/feed" rel="self" type="application/rss+xml"/><title>physicshelpline - Question of the day , Modern Physics</title><description>physicshelpline - Question of the day , Modern Physics</description><link>https://www.physicshelpline.com/Question/modern-physics</link><lastBuildDate>Sat, 20 Jun 2026 21:58:25 +0530</lastBuildDate><generator>http://zoho.com/sites/</generator><item><title><![CDATA[Radioactivity ]]></title><link>https://www.physicshelpline.com/Question/post/radioactivity</link><description><![CDATA[Q- Isotope 137 Cs of Cesium has a half life of 30 years. Suppose a distributor sells 5 grams of it in January 1, 2000. (a) Write an equation with givi ]]></description><content:encoded><![CDATA[<div class="zpcontent-container blogpost-container "><div data-element-id="elm_bQxkB7E6SbO3Bc5zkYXkDQ" data-element-type="section" class="zpsection "><style type="text/css"></style><div class="zpcontainer-fluid zpcontainer"><div data-element-id="elm__PT-9eeoNhrCenOdA-VPGg" data-element-type="row" class="zprow zprow-container zpalign-items-flex-start zpjustify-content-flex-start zpdefault-section zpdefault-section-bg " data-equal-column="false"><style type="text/css"></style><div data-element-id="elm__nJklc5N5jF-QuF2KFOaRg" data-element-type="column" class="zpelem-col zpcol-12 zpcol-md-12 zpcol-sm-12 zpalign-self- zpdefault-section zpdefault-section-bg "><style type="text/css"></style><div data-element-id="elm_j5p-VkUGB_hGx9o4n6II9A" data-element-type="text" class="zpelement zpelem-text "><style></style><div class="zptext zptext-align-left zptext-align-mobile-left zptext-align-tablet-left " data-editor="true"><p></p><div><p style="text-align:justify;"><span>Q- Isotope 137 Cs of Cesium has a half life of 30 years. Suppose a distributor sells 5 grams of it in January 1, 2000. (a) Write an equation with giving the number of grams of the isotope left &quot;t&quot; years after January 1, 2000. (b) How many grams are present after 6 years?</span></p><p style="text-align:justify;"><strong style="font-style:italic;text-decoration-line:underline;"><a href="/files/modern/26.01.16.pdf" target="_blank" rel="">Solution:</a></strong></p></div><p></p></div>
</div></div></div></div></div></div> ]]></content:encoded><pubDate>Fri, 16 Jan 2026 17:47:50 +0530</pubDate></item></channel></rss>