{"id":3414,"date":"2025-07-21T11:09:31","date_gmt":"2025-07-21T11:09:31","guid":{"rendered":"https:\/\/odeacademy.in\/?p=3414"},"modified":"2025-07-21T11:09:31","modified_gmt":"2025-07-21T11:09:31","slug":"electricity-and-magnetic-effects-of-current","status":"publish","type":"post","link":"https:\/\/thequickknowledge.com\/exam\/electricity-and-magnetic-effects-of-current\/","title":{"rendered":"Electricity &#038; Magnetic Effects of Current &#8211; Physics | General Science"},"content":{"rendered":"<h4 style=\"text-align: center;\">Electricity and Magnetic Effects of Electric Current<\/h4>\n<hr \/>\n<p data-start=\"175\" data-end=\"612\"><strong>Electric Current<\/strong> is the flow of electric charge through a conductor. Electric current (I) is defined as the rate of flow of charge (Q) through a point in a circuit per unit time (t). <strong data-start=\"730\" data-end=\"743\">I = Q \/ t<\/strong>.<\/p>\n<ul>\n<li data-start=\"175\" data-end=\"612\">SI unit of Electric current (I) is <strong data-start=\"762\" data-end=\"776\">Ampere (A)<\/strong> One ampere equals one <strong>Coulomb per second<\/strong>.<\/li>\n<\/ul>\n<p data-start=\"857\" data-end=\"1298\"><strong>Potential Difference (V)<\/strong> between two points is the work done (W) in moving a unit charge (Q) between those points: <strong data-start=\"1069\" data-end=\"1082\">V = W \/ Q<\/strong>.<\/p>\n<ul>\n<li data-start=\"857\" data-end=\"1298\">SI unit of potential difference (V) is <strong data-start=\"1101\" data-end=\"1113\">volt (V)<\/strong>. One volt equals one <strong>joule per coulomb<\/strong>.<\/li>\n<li data-start=\"857\" data-end=\"1298\">The instrument used to measure potential difference is a <strong data-start=\"1245\" data-end=\"1258\">Voltmeter<\/strong>, which is always connected in parallel.<\/li>\n<\/ul>\n<p><strong data-start=\"673\" data-end=\"686\">Ohm\u2019s Law<\/strong> establishes the relationship between the <strong data-start=\"728\" data-end=\"756\">Potential Difference (V)<\/strong> across a conductor and the <strong data-start=\"784\" data-end=\"799\">Current (I)<\/strong> flowing through it. it&#8217;s observed that the ratio V\/I remains constant, which implies a straight-line graph. This constant ratio is called <strong data-start=\"1032\" data-end=\"1050\">Resistance (R)<\/strong>. The mathematical forms of Ohm\u2019s Law: <strong><span class=\"katex\"><span class=\"katex-mathml\">V \u221d R (<\/span><\/span><span class=\"katex\"><span class=\"katex-mathml\">V = IR)<\/span><\/span><\/strong><\/p>\n<ul>\n<li data-start=\"1092\" data-end=\"1109\">SI unit of resistance is <strong>ohm (\u03a9)<\/strong>, defined as 1 volt per 1 ampere. A device called a <strong>Rheostat<\/strong> is used to vary resistance and hence control the current.<\/li>\n<\/ul>\n<p data-start=\"1092\" data-end=\"1109\"><strong>Factors on Which Resistance Depends<\/strong><\/p>\n<ul>\n<li data-start=\"1092\" data-end=\"1109\">Longer wires have more resistance. <span class=\"katex\"><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"mord mathnormal\">R <\/span><span class=\"mrel\">\u221d <\/span><\/span><span class=\"base\"><span class=\"mord mathnormal\">L<\/span><\/span><\/span><\/span> (length)<\/li>\n<li data-start=\"1092\" data-end=\"1109\">Thicker wires have less resistance. <span class=\"katex\"><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"mord mathnormal\">R <\/span><span class=\"mrel\">\u221d <\/span><\/span><span class=\"base\"><span class=\"mord\"><span class=\"mfrac\"><span class=\"vlist-t vlist-t2\"><span class=\"vlist-r\"><span class=\"vlist\"><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\"><span class=\"mord mathnormal mtight\">1\/<\/span><\/span><\/span><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\">A<\/span><\/span><\/span><span class=\"vlist-s\">\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span> (cross-sectional area)<\/li>\n<li data-start=\"1092\" data-end=\"1109\">Combining both R\u00a0=\u00a0\u03c1\u00a0(L\/A). Here, <span class=\"katex\"><span class=\"katex-mathml\">\u03c1<\/span><\/span>\u00a0is <strong data-start=\"888\" data-end=\"903\">resistivity<\/strong>, a material-specific constant. Its unit is <strong data-start=\"947\" data-end=\"954\">\u03a9\u00b7m<\/strong>.<\/li>\n<\/ul>\n<p data-start=\"988\" data-end=\"1016\"><strong>Materials are classified as Resistivity:<\/strong><\/p>\n<ul data-start=\"1017\" data-end=\"1245\">\n<li><strong data-start=\"1019\" data-end=\"1033\">Conductors<\/strong>: Silver, Copper, Aluminium, etc. (very low resistivity)<\/li>\n<li><strong data-start=\"1092\" data-end=\"1102\">Alloys<\/strong>: Nichrome, Constantan, etc. (higher resistivity but stable at high temperature)<\/li>\n<li><strong data-start=\"1185\" data-end=\"1199\">Insulators<\/strong>: Glass, Ebonite, etc. (very high resistivity)<\/li>\n<\/ul>\n<p><strong>Resistors in Series and Parallel<\/strong><\/p>\n<p style=\"padding-left: 40px;\">In series, resistors are connected end-to-end and the same current flows through each. the potential difference across a series of three resistors using a voltmeter and confirming that the total voltage (V) across the combination is equal to the sum of the voltages across individual resistors: V = V\u2081 + V\u2082 + V\u2083, This is followed by the application of Ohm&#8217;s Law for resistors in series, showing that the total resistance (R\u209b) in a series is: R\u209b = R\u2081 + R\u2082 + R\u2083<\/p>\n<p style=\"padding-left: 40px;\">In parallel, resistors are connected across the same two points, offering multiple paths for current and \u00a0potential difference across each resistor is the same.<\/p>\n<p style=\"padding-left: 40px;\" data-start=\"46\" data-end=\"273\"><strong data-start=\"79\" data-end=\"100\">parallel circuits<\/strong> and <strong data-start=\"105\" data-end=\"129\">current distribution<\/strong> across resistors. A key observation is that the total current <span class=\"katex\"><span class=\"katex-mathml\">II<\/span><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"mord mathnormal\">I<\/span><\/span><\/span><\/span> in a parallel circuit is the <strong data-start=\"229\" data-end=\"270\">sum of the individual branch currents<\/strong>: <span class=\"katex-display\"><span class=\"katex\"><span class=\"katex-mathml\">I = I1 + I2 + I3<\/span><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"mord\"><span class=\"msupsub\"><span class=\"vlist-t vlist-t2\"><span class=\"vlist-r\"><span class=\"vlist-s\">\u200b<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n<p style=\"padding-left: 40px;\" data-start=\"301\" data-end=\"410\">Using Ohm\u2019s Law <span class=\"katex\"><span class=\"katex-mathml\">I=V\/R<\/span><\/span>, the concept of <strong data-start=\"347\" data-end=\"393\">equivalent resistance in parallel circuits<\/strong> is derived as: <span class=\"katex-display\"><span class=\"katex\"><span class=\"katex-mathml\">1\/Rp = 1\/R1 + 1\/ R2 + 1\/ R3<\/span><\/span><\/span><\/p>\n<p style=\"padding-left: 40px;\" data-start=\"647\" data-end=\"1012\"><strong>Difference between series and parallel circuits<\/strong> is highlighted. Series circuits carry the same current throughout but are impractical when devices need different currents. A break in one component stops the entire circuit. In contrast, parallel circuits are more reliable for domestic usage as the current divides and each component functions independently.<\/p>\n<p data-start=\"1014\" data-end=\"1263\"><span data-start=\"1033\" data-end=\"1071\">H<\/span><strong data-start=\"1033\" data-end=\"1071\">eating effect of electric current,<\/strong>\u00a0When current flows through a resistor, energy is used and converted into heat. This is utilized in devices like heaters and irons. The heat produced is given by: <span class=\"katex-display\"><span class=\"katex\"><span class=\"katex-mathml\">H = V I t<\/span><\/span><\/span><\/p>\n<p><span class=\"katex-display\"><span class=\"katex\"><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"mord\"><span class=\"mfrac\"><span class=\"vlist-t vlist-t2\"><span class=\"vlist-r\"><span class=\"vlist-s\">\u200b <strong data-start=\"184\" data-end=\"210\">Joule\u2019s law of heating<\/strong>, which states that the heat produced in a resistor is proportional to the square of the current, the resistance, and the time. The <strong data-start=\"342\" data-end=\"362\">electrical power<\/strong> concept is introduced as the rate at which electric energy is consumed in a circuit, expressed as P =\u00a0VI = I<sup>2<\/sup>R\u00a0= V<sup>2<\/sup>R, <\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>Electric power is measured in watts, and commercial consumption is measured in kilowatt-hours (kWh).<\/p>\n<p>When electric current flows through a conductor, it generates a magnetic field. Magnetic field lines are imaginary lines; they emerge from the north pole and merge at the south pole. The strength of the magnetic field is higher where the lines are close together.<\/p>\n<p><strong>Right-Hand Thumb Rule<\/strong> : Thumb in direction of current, curled fingers show magnetic field lines. If current flows east to west, then: Magnetic field below the wire: clockwise. Magnetic field above the wire: anti-clockwise.<\/p>\n<p><strong>Magnetic Field due to a Circular Loop<\/strong> When the wire is bent into a loop, the magnetic field lines form concentric circles at every point. At the center of the loop, the field lines appear as straight lines. All sections of the loop contribute to the magnetic field in the same direction at the center.<\/p>\n<p><strong data-start=\"179\" data-end=\"246\">magnetic field due to a current in a circular coil and solenoid<\/strong>. When current passes through a circular coil, it produces a magnetic field similar to that of a bar magnet. If the coil has multiple turns, the magnetic field becomes stronger. A <strong data-start=\"426\" data-end=\"438\">solenoid<\/strong>, which is a coil of many circular turns wrapped closely in a cylinder, produces a <strong data-start=\"521\" data-end=\"547\">uniform magnetic field<\/strong> inside it. This uniform field is similar to that of a bar magnet, with one end acting as the north pole and the other as the south. This magnetic field can be used to magnetize materials like soft iron, forming an electromagnet.<\/p>\n<p data-start=\"681\" data-end=\"1062\"><strong data-start=\"804\" data-end=\"865\">force on a current-carrying conductor in a magnetic field<\/strong>. An experiment shows that a current-carrying conductor placed in a magnetic field experiences a force, and this force changes direction when the direction of current or magnetic field is reversed.<\/p>\n<p data-start=\"1064\" data-end=\"1327\"><strong data-start=\"1092\" data-end=\"1120\">Fleming&#8217;s Left-Hand Rule<\/strong>, helps to determine the direction of motion\/force when current and magnetic field directions are known. This principle is applied in electric motors, generators, and loudspeakers.<\/p>\n<hr \/>\n<p><span style=\"color: #ff0000;\"><strong>Related Links<\/strong><\/span><\/p>\n<ul>\n<li>General Science : Questions for Competitive Exams<\/li>\n<\/ul>\n<p><strong><a href=\"https:\/\/thequickknowledge.com\/exam\/general-science\/\">General Science<\/a>, <a href=\"https:\/\/thequickknowledge.com\/exam\/study-materials\/\">Study Materials<\/a>, <a href=\"https:\/\/thequickknowledge.com\/exam\/current-affairs\/\">Current Affairs<\/a>, <a href=\"https:\/\/thequickknowledge.com\/exam\/practice-questions\/\">Practice Questions<\/a>,\u00a0<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Electricity and Magnetic Effects of Electric Current Electric Current is the flow of electric charge through a conductor. Electric current (I) is defined as the rate of flow of charge (Q) through a point in a circuit per unit time (t). I = Q \/ t. SI unit of Electric current (I) is Ampere (A) [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"no-sidebar","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":"disabled","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","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":[137],"tags":[138],"class_list":["post-3414","post","type-post","status-publish","format-standard","hentry","category-general-science","tag-general-science-notes"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/thequickknowledge.com\/exam\/wp-json\/wp\/v2\/posts\/3414","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/thequickknowledge.com\/exam\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/thequickknowledge.com\/exam\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/thequickknowledge.com\/exam\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/thequickknowledge.com\/exam\/wp-json\/wp\/v2\/comments?post=3414"}],"version-history":[{"count":2,"href":"https:\/\/thequickknowledge.com\/exam\/wp-json\/wp\/v2\/posts\/3414\/revisions"}],"predecessor-version":[{"id":3418,"href":"https:\/\/thequickknowledge.com\/exam\/wp-json\/wp\/v2\/posts\/3414\/revisions\/3418"}],"wp:attachment":[{"href":"https:\/\/thequickknowledge.com\/exam\/wp-json\/wp\/v2\/media?parent=3414"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/thequickknowledge.com\/exam\/wp-json\/wp\/v2\/categories?post=3414"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/thequickknowledge.com\/exam\/wp-json\/wp\/v2\/tags?post=3414"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}