{"id":2577,"date":"2022-04-22T19:37:36","date_gmt":"2022-04-22T19:37:36","guid":{"rendered":"https:\/\/mdr.foobrdigital.com\/?p=2577"},"modified":"2022-04-22T19:37:36","modified_gmt":"2022-04-22T19:37:36","slug":"ohms-law","status":"publish","type":"post","link":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/2022\/04\/22\/ohms-law\/","title":{"rendered":"Ohm’s Law"},"content":{"rendered":"\n

Ohm\u2019s law states the relationship between electric current and potential difference. The current that flows through most conductors is directly proportional to the voltage applied to it. Georg Simon Ohm, a German physicist was the first to verify Ohm\u2019s law experimentally.<\/p>\n\n\n\n

One of the most basic and important laws of electric circuits is Ohm\u2019s law.<\/p>\n\n\n\n

Ohm\u2019s law states that the voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions and temperature remain constant.<\/p><\/blockquote>\n\n\n\n

Mathematically, this current-voltage relationship is written as,<\/strong><\/p>\n\n\n\n

\"Ohm's<\/figure>\n\n\n\n

In the equation, the constant of proportionality, R is Resistance and has units of ohms, with symbol \u03a9.<\/strong><\/p>\n\n\n\n

The same formula can be rewritten in order to calculate the current and resistance respectively as follows:<\/p>\n\n\n\n

\"Ohm's<\/figure>\n\n\n\n
\"\"<\/figure>\n\n\n\n

Ohm\u2019s law only holds true if the provided temperature and the other physical factors remain constant.<\/ins>\u00a0In certain components, increasing the current raises the\u00a0temperature. An example of this is the filament of a light bulb, in which the temperature rises as the current is increased. In this case, Ohm\u2019s law cannot be applied.\u00a0The lightbulb filament violates Ohm\u2019s Law<\/strong>.<\/p>\n\n\n\n

Ohm\u2019s Law Statement<\/ins>:<\/strong> Ohm\u2019s law states that the voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions and temperature, remain constant.Ohm\u2019s Law Equation<\/ins>:<\/strong> V = IR, where V is the voltage across the conductor, I is the current flowing through the conductor and R is the resistance provided by the conductor to the flow of current.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

<\/p>\n\n\n\n


Analyzing row 1,2 and 3, we come to understand that doubling and tripling the voltage leads to doubling and a tripling of the current in the circuit. Likewise, when we compare rows 1 and 4 and rows 2 and 5, we come to understand that doubling the total resistance serves to halve the current in the circuit.<\/p>\n\n\n\n

Water Pipe Analogy for Ohm\u2019s Law<\/h3>\n\n\n\n

Ohm\u2019s Law describes the current flow through a resistance when different electric potentials (voltage) are applied at each end of the\u00a0resistance. Since we can\u2019t see electrons, the water-pipe analogy helps us understand the electric circuits better. Water flowing through pipes is a good mechanical system that is analogous to an electrical circuit.<\/p>\n\n\n\n

Here, the voltage is analogous to water pressure, the current is the amount of water flowing through the pipe, and the resistance is the size of the pipe. More water will flow through the pipe (current) when more pressure is applied (voltage) and the bigger the pipe, (lower the resistance).<\/p>\n\n\n\n

<\/p>\n\n\n\n

Experimental Verification of Ohm\u2019s Law<\/h2>\n\n\n\n

Ohm\u2019s Law can be easily verified by the following experiment:<\/p>\n\n\n\n

Appartus Required:<\/ins><\/strong><\/p>\n\n\n\n

  • Resistor<\/li>
  • Ammeter<\/li>
  • Voltmeter<\/li>
  • Battery<\/li>
  • Plug Key<\/li>
  • Rheostat<\/li><\/ul>\n\n\n\n

    Circuit Diagram:<\/ins><\/strong>
    <\/p>\n\n\n\n

    \"\"<\/figure>\n\n\n\n

    Procedure:<\/ins><\/strong><\/p>\n\n\n\n

    1. Initially, the key K is closed and the rheostat is adjusted to get the minimum reading in Ammeter A and voltmeter.<\/li>
    2. The current in the circuit is increased gradually by moving the sliding terminal of the rheostat. During the process, the current flowing in the circuit and the corresponding value of potential difference across the resistance wire R are recorded.<\/li>
    3. This way different sets of values of voltage and current are obtained.<\/li>
    4. For each set of values of V and I, the ratio of V\/I is calculated.<\/li>
    5. When you calculate the ratio V\/I for each case, you will come to notice that it is almost the same. So V\/I = R, which is a constant.<\/li>
    6. Plot a graph of the current against the potential difference, it will be a straight line. This shows that the current is proportional to the potential difference.<\/li><\/ol>\n\n\n\n

      Similar Reading:<\/ins><\/strong><\/p>\n\n\n\n

      • Kirchhoff\u2019s Law<\/li>
      • Faraday\u2019s Laws<\/li>
      • Laws of Thermodynamics<\/li><\/ul>\n\n\n\n

        Ohm\u2019s Law Magic Triangle<\/h2>\n\n\n\n

        You can make use of the Ohm\u2019s law magic triangle to remember the different equations for Ohm\u2019s law used to solve for different variables(V, I, R).
        <\/p>\n\n\n\n

        \"\"<\/figure>\n\n\n\n


        If the value of voltage is asked and the values of the current and resistance are given, then to calculate voltage simply cover\u00a0V<\/strong>\u00a0at the top. So, we are left with the\u00a0I<\/strong>\u00a0and\u00a0R<\/strong>\u00a0or\u00a0I X R<\/strong>. So, the equation for Voltage is Current multiplied by Resistance. Examples of how the magic triangle is employed to determine the voltage using Ohm\u2019s law is given below.<\/p>\n\n\n\n

        Ohm\u2019s Law Solved Problems<\/h3>\n\n\n\n

        Example 1: If the resistance of an electric iron is 50 \u03a9 and a current of 3.2 A flows through the resistance. Find the voltage between two points.<\/strong><\/p>\n\n\n\n

        Solution:<\/ins><\/strong><\/p>\n\n\n\n

        If we are asked to calculate the value of voltage with the value of current and resistance given to us, then cover V in the triangle. Now, we are left with I and R or more precisely I \u00d7 R.<\/p>\n\n\n\n

        Therefore, we use the following formula to calculate the value of V:<\/p>\n\n\n\n

        V = I \u00d7 R<\/strong><\/p>\n\n\n\n

        Substituting the values in the equation, we get<\/p>\n\n\n\n

        V = 3.2 A \u00d7 50 \u00f7 = 160 V<\/strong><\/p>\n\n\n\n

        V = 160V<\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

        Example 2: An EMF source of 8.0 V is connected to a purely resistive electrical appliance (a light bulb). An electric current of 2.0 A flows through it. Consider the conducting wires to be resistance-free. Calculate the resistance offered by the electrical appliance.<\/strong><\/p>\n\n\n\n

        Solution:<\/ins><\/strong><\/p>\n\n\n\n

        When we are asked to find out the value of resistance when the values of voltage and current are given, then we cover R in the triangle. This leaves us with only V and I, more precisely V \u00f7 I.<\/p>\n\n\n\n

        Substituting the values in the equation, we get<\/p>\n\n\n\n

        R = V \u00f7 I<\/strong><\/p>\n\n\n\n

        R = 8 V \u00f7 2 A = 4 \u03a9<\/strong><\/p>\n\n\n\n

        R = 4 \u03a9<\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

        Calculating Electrical Power Using Ohm\u2019s Law<\/h2>\n\n\n\n

        The rate at which energy is converted from the electrical energy of the moving charges to some other form of energy like mechanical energy, heat, magnetic fields or energy stored in electric fields, is known as electric power. The unit of power is the watt. The electrical power can be calculated using the Ohm\u2019s law and by substituting the values of voltage, current and resistance.<\/p>\n\n\n\n

        Formula to find power<\/h3>\n\n\n\n

        When the values for voltage and current are given,<\/strong>
        \"Power
        When the values for voltage and resistance are given,<\/strong>
        \"Power
        When the values for current and resistance are given,<\/strong>
        \"Power<\/p>\n\n\n\n

        What is a Power Triangle?<\/h3>\n\n\n\n
        \"\"<\/figure>\n\n\n\n

        The power triangle can be employed to determine the value of electric power, voltage and current when the values of the other two parameters are given to us. In the power triangle, the power (P) is on the top and current(I) and voltage (V) are at the bottom.<\/p>\n\n\n\n

        When the values of current and voltage are given, the formula for finding power is,<\/strong>
        \"\"
        When the values of power and voltage is given, the formula for finding current is,<\/strong>
        \"\"
        When the values of power and current is given, the formula for finding voltage is,<\/strong>
        \"\"<\/p>\n\n\n\n

        Ohm\u2019s Law Pie Chart<\/h2>\n\n\n\n

        To better understand the relationship between various parameters, we can take all the equations used to find the voltage, current, resistance and power, and condense them into a simple Ohm\u2019s Law pie chart as shown below.
        <\/p>\n\n\n\n

        \"\"<\/figure>\n\n\n\n

        Ohm\u2019s Law Matrix Table<\/h2>\n\n\n\n

        Like Ohm\u2019s Law Pie Chart shown above, we can condense the individual Ohm\u2019s Law equations into a simple matrix table as shown below for easy reference when calculating an unknown value.
        <\/p>\n\n\n\n

        \"\"<\/figure>\n\n\n\n

        Ohm\u2019s Law Applications<\/h2>\n\n\n\n

        The main applications of Ohm\u2019s law are:<\/p>\n\n\n\n

        • To determine the voltage, resistance or current of an electric circuit.<\/li>
        • Ohm\u2019s law is used to maintain the desired voltage drop across the electronic components.<\/li>
        • Ohm\u2019s law is also used in DC ammeter and other DC shunts to divert the current.<\/li><\/ul>\n\n\n\n

          Limitations of Ohm\u2019s Law<\/h3>\n\n\n\n

          Following are the limitations of Ohm\u2019s law:<\/p>\n\n\n\n

          • Ohm\u2019s law is not applicable for unilateral electrical elements like diodes and transistors as they allow the current to flow through in one direction only.<\/li>
          • For non-linear electrical elements with parameters like capacitance, resistance etc the voltage and current won\u2019t be constant with respect to time making it difficult to use Ohm\u2019s law.<\/li><\/ul>\n\n\n\n

            <\/p>\n\n\n\n

            Frequently Asked Questions \u2013 FAQs<\/h2>\n\n\n\n

            What does Ohm\u2019s law state?<\/h3>\n\n\n\n

            Ohm\u2019s law states that the current through a conductor between two points is directly proportional to the voltage across the two points.<\/p>\n\n\n\n

            What can Ohm\u2019s Law be used for?<\/h3>\n\n\n\n

            Ohm\u2019s law is used to validate the static values of circuit components such as current levels, voltage supplies, and voltage drops.<\/p>\n\n\n\n

            Is Ohm\u2019s Law Universal?<\/h3>\n\n\n\n

            No. Ohm\u2019s law is not a universal law. This is because ohm\u2019s law is only applicable to ohmic conductors such as iron and copper but is not applicable to non-ohmic conductors such as semiconductors.<\/p>\n\n\n\n

            Why is Ohm\u2019s law not applicable to semiconductors?<\/h3>\n\n\n\n

            Ohm\u2019s law doesn\u2019t apply to semiconducting devices because they are nonlinear devices. This means that the ratio of voltage to current doesn\u2019t remain constant for variations in voltage.<\/p>\n\n\n\n

            When does Ohm\u2019s law fail?<\/h3>\n\n\n\n

            Ohm\u2019s law fails to explain the behaviour of semiconductors and unilateral devices such as diodes. Ohm\u2019s law may not give the desired results if the physical conditions such as temperature or pressure are not kept constant.<\/p>\n","protected":false},"excerpt":{"rendered":"

            Ohm\u2019s law states the relationship between electric current and potential difference. The current that flows through most conductors is directly proportional to the voltage applied to it. Georg Simon Ohm, a German physicist was the first to verify Ohm\u2019s law experimentally. One of the most basic and important laws of electric circuits is Ohm\u2019s law. […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[238],"tags":[],"_links":{"self":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/posts\/2577"}],"collection":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/comments?post=2577"}],"version-history":[{"count":0,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/posts\/2577\/revisions"}],"wp:attachment":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/media?parent=2577"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/categories?post=2577"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/tags?post=2577"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}