{"id":9492,"date":"2026-06-01T21:33:48","date_gmt":"2026-06-01T21:33:48","guid":{"rendered":"https:\/\/kapdec.com\/help\/?p=9492"},"modified":"2026-06-01T21:33:48","modified_gmt":"2026-06-01T21:33:48","slug":"electric-field-and-electric-potential","status":"publish","type":"post","link":"https:\/\/kapdec.com\/help\/electric-field-and-electric-potential\/","title":{"rendered":"Electric Field And Electric Potential"},"content":{"rendered":"

Unit: <\/strong>Electrostatics<\/strong><\/h1>\n

Chapter: Electric Field and electric potential<\/strong><\/h2>\n

Reference: AP Physics Electricity and Magnetism, <\/em>Electric Field, Electrostatic Potential, Electric Potential Difference, Unit for Electric Potential, Potential due to a Point Charge, Conservation of electric energy<\/p>\n

After studying this chapter, you should be able to,<\/strong><\/p>\n

    \n
  • State the concept of electric field<\/strong><\/li>\n
  • Explain the concept of Electrostatic Potential<\/strong><\/li>\n<\/ul>\n

    Electric Field<\/strong><\/p>\n

    • The space around a charge up to which its force can be experienced is called the electric field.<\/p>\n

    • Electric field due to a point charge q has a magnitude<\/p>\n

    \"\"<\/p>\n

      \n
    • It is radially outwards if q is positive.<\/li>\n
    •  It is radially inwards if q is negative.<\/li>\n
    • The electric field satisfies the superposition principle.<\/li>\n
    •  The unit of the electric field is N\/C.<\/li>\n
    •  The electric field inside the cavity of a charged conductor is zero.<\/li>\n<\/ul>\n

      Electrostatic Potential<\/strong><\/p>\n

      The electrostatic potential<\/strong> (V) at any point in a region with the electrostatic field is the work done in bringing a unit positive charge (without acceleration<\/strong>) from infinity to that point. If 'W' is the work done in moving a charge ‘q’ from infinity to a point, then the potential at that point is V = W \/ q.<\/p>\n

      Electric Potential Difference<\/strong><\/p>\n

      Similar to electric potential, the electric potential difference<\/strong> is the work done by external force in bringing a unit positive charge from point R to point P. i.e.,<\/p>\n

      \"\"<\/p>\n

      Here VP<\/sub> and VR<\/sub> are the electrostatic potentials at P and R, respectively, and UP<\/sub> and UR<\/sub> are the potential energies of a charge<\/strong> q when it is at P and at R respectively.<\/p>\n

      Unit for Electric Potential<\/strong><\/p>\n

      The unit of measurement for electric potential<\/strong> is the volt, so the electric potential is often called voltage<\/strong>. A potential of 1 volt (V) equals 1 joule (J) of energy per 1 coulomb (C) of charge.<\/p>\n

      \"\"<\/p>\n

      Potential due to a Point Charge<\/strong><\/p>\n

      Consider a point charge<\/strong> q placed at point O. Consider any point P in the field of the above charge. Let us calculate the potential<\/strong> at point P due to the charge q kept at point O. Since the work done is independent of the path, we choose a convenient path, along the radial direction.<\/p>\n

      \"\"<\/p>\n

      Let the distance OP = r.<\/p>\n

      The electric force at P, due to q will be directed along OP, given by<\/p>\n

      \"\"<\/p>\n

      And electric potential is,<\/p>\n

      \"\"<\/p>\n

      Conservation of electric energy<\/strong><\/p>\n

        \n
      • The conservation of electric energy, also known as the conservation of electrical energy or the law of conservation of energy applied to electricity, states that electric energy cannot be created or destroyed; it can only be converted from one form to another or transferred between different components in an electrical system. This principle is a fundamental concept in physics and is based on the broader principle of conservation of energy, which applies to all forms of energy.<\/li>\n
      • In an isolated electrical system, where no energy is added or removed from the system, the total electric energy remains constant over time. However, it is important to note that energy losses can occur due to factors such as resistance, heat dissipation, or inefficiencies in electrical devices. These losses result in a conversion of electric energy into other forms, such as heat or sound.<\/li>\n
      • In practical applications, it is crucial to minimize energy losses in electrical systems to increase efficiency and reduce waste. This can be achieved through various means, including using conductors with low resistance, optimizing circuit designs, and employing energy-efficient devices.<\/li>\n
      • The conservation of electric energy is a fundamental principle in the analysis and design of electrical systems, and it plays a crucial role in fields such as electrical engineering, power generation and distribution, and renewable energy systems. By understanding and applying this principle, engineers and scientists can develop more efficient and sustainable electrical systems.<\/li>\n<\/ul>\n

        Example:<\/strong> (a) Calculate the potential at a point P due to a charge of 4 × 10–7<\/sup>C located 9 cm away. (b) Hence obtain the work done in bringing a charge of 2 × 10–9<\/sup> C from infinity to the point P. Does the answer depend on the path along which the charge is brought?<\/p>\n

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

        (a)<\/p>\n

        \"\"<\/p>\n

        (b)     W=VQ  = 4X104<\/sup> X 2 X 10-9 <\/sup> = 6<\/p>\n

        No, the work done will be path independent.<\/p>\n

        Key points:<\/strong><\/p>\n

        Electric field:<\/strong><\/p>\n

        Definition: An electric field is a region of space around a charged object or collection of charged objects in which a force would be exerted on other charged objects.<\/p>\n

        Electric Field Strength:<\/strong> The electric field strength at a point in space is defined as the force experienced by a positive test charge placed at that point, divided by the magnitude of the test charge.<\/p>\n

        The direction of the Electric Field:<\/strong> The electric field points in the direction that a positive test charge would experience a force if placed in the field. It is conventionally defined as the direction in which a positive charge would move.<\/p>\n

        Electric Field Lines:<\/strong> Electric field lines are a visual representation of the electric field. They are drawn as lines that start on positive charges and end on negative charges or extend to infinity if the charges are not confined.<\/p>\n

        Electric Field due to Point Charges:<\/strong> The electric field produced by a point charge decreases with distance from the charge and follows an inverse square law. It is given by the equation E = kQ\/r2<\/sup>, where E is the electric field, k is the electrostatic constant (8.99 x 109 <\/sup>Nm2<\/sup>\/C2<\/sup>), Q is the charge, and r is the distance from the charge.<\/p>\n

        Electric Potential:<\/strong><\/p>\n

        Definition:<\/strong> Electric potential, also known as voltage, is a measure of the electric potential energy per unit charge at a point in space. It represents the work done in bringing a positive test charge from infinity to that point.<\/p>\n

        Potential Difference:<\/strong> The potential difference between two points is the work done per unit charge in moving a positive test charge from one point to the other. It is measured in volts (V).<\/p>\n

        Electric Potential Energy:<\/strong> The electric potential energy of a charge at a point in an electric field is given by the product of the charge and the electric potential at that point.<\/p>\n

        Calculation of Electric Potential:<\/strong> The electric potential at a point due to a point charge is given by the equation V = kQ\/r, where V is the electric potential, k is the electrostatic constant (8.99 x 109<\/sup> Nm2<\/sup>\/C2<\/sup>), Q is the charge, and r is the distance from the charge.<\/p>\n

        Equipotential Surfaces:<\/strong> Equipotential surfaces are imaginary surfaces in space where the electric potential is the same at all points. They are perpendicular to the electric field lines and indicate regions of constant electric potential. No work is done in moving a charge along an equipotential surface.<\/p>\n","protected":false},"excerpt":{"rendered":"

        Unit: Electrostatics Chapter: Electric Field and electric potential Reference: AP Physics Electricity and Magnetism, Electric Field, Electrostatic Potential, Electric Potential Difference, Unit for Electric Potential, Potential due to a Point Charge, Conservation of electric energy After studying this chapter, you should be able to, State the concept of electric field Explain the concept of Electrostatic […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[625],"tags":[],"class_list":["post-9492","post","type-post","status-publish","format-standard","hentry","category-ap-physics-c-electricity-magnetism"],"_links":{"self":[{"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/posts\/9492","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/comments?post=9492"}],"version-history":[{"count":0,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/posts\/9492\/revisions"}],"wp:attachment":[{"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/media?parent=9492"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/categories?post=9492"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/tags?post=9492"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}