{"id":222242,"date":"2025-05-31T07:15:38","date_gmt":"2025-05-31T07:15:38","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=222242"},"modified":"2025-05-31T07:15:41","modified_gmt":"2025-05-31T07:15:41","slug":"part-a-what-is-the-phase-relationship-between-current-and-voltage-for-a-pure-resistance","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/31\/part-a-what-is-the-phase-relationship-between-current-and-voltage-for-a-pure-resistance\/","title":{"rendered":"Part A What is the phase relationship between current and voltage for a pure resistance"},"content":{"rendered":"\n

Part A What is the phase relationship between current and voltage for a pure resistance? O current leads voltage by 90 O current lags voltage by 90\u00b0 O current and voltage are in phase Submit Part B For an inductance? current leads voltage by 90 O current lags voltage by O current and voltage are in phase<\/p>\n\n\n\n

The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n

Correct Answers<\/strong><\/h3>\n\n\n\n

Part A:<\/strong> For a pure resistance, current and voltage are in phase<\/strong>.
Part B:<\/strong> For a pure inductance, current lags voltage by 90\u00b0<\/strong>.<\/p>\n\n\n\n

\n\n\n\n

Explanation <\/strong><\/h3>\n\n\n\n

In AC (alternating current) circuits<\/strong>, the phase relationship between current<\/strong> and voltage<\/strong> depends on the type of component\u2014resistor<\/strong>, inductor<\/strong>, or capacitor<\/strong>.<\/p>\n\n\n\n

\n\n\n\n

Part A: Pure Resistance<\/strong><\/h4>\n\n\n\n

In a circuit with only a resistor<\/strong>, the current and voltage are in phase<\/strong>. This means the peaks, zero crossings, and troughs of the current waveform occur at the same time as those of the voltage waveform.<\/p>\n\n\n\n

This is because, according to Ohm’s Law<\/strong> (V = IR), the current is directly proportional to the voltage. When the voltage increases or decreases, the current does the same simultaneously. There is no time delay<\/strong> (or phase shift) between them. The power<\/strong> consumed in a resistive circuit is entirely real (not reactive), and it is converted into heat or work.<\/p>\n\n\n\n

\n\n\n\n

Part B: Pure Inductance<\/strong><\/h4>\n\n\n\n

In a circuit with only an inductor<\/strong>, the current lags the voltage by 90 degrees<\/strong> (\u03c0\/2 radians). This happens because an inductor resists changes in current<\/strong> due to its magnetic field. According to Faraday\u2019s Law, the voltage across an inductor is proportional to the rate of change of current<\/strong> (V = L * di\/dt).<\/p>\n\n\n\n

So, when the voltage is at its maximum<\/strong>, the rate of change of current is also at its maximum\u2014but the current itself is still increasing and has not peaked yet. The current reaches its peak a quarter cycle (90\u00b0)<\/strong> after the voltage does, hence it lags<\/strong>.<\/p>\n\n\n\n

In a purely inductive circuit, no real power is consumed<\/strong> over time\u2014the energy is temporarily stored in the magnetic field and then returned to the source.<\/p>\n\n\n\n

\n\n\n\n

These phase relationships are crucial in designing and analyzing AC circuits, power systems, and in understanding reactive power in inductive and capacitive loads.<\/p>\n\n\n\n

\"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

Part A What is the phase relationship between current and voltage for a pure resistance? O current leads voltage by 90 O current lags voltage by 90\u00b0 O current and voltage are in phase Submit Part B For an inductance? current leads voltage by 90 O current lags voltage by O current and voltage are […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-222242","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/222242","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=222242"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/222242\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=222242"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=222242"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=222242"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}