Fundamentals of Physics 8/e 22 - Finding the Electric Field－I D. Halliday, R. Resnick, and J. Walker 國立彰化師大教學卓越計畫 理學院普通物理整合型教材 主持人：郭艷光院長

彰化師大教學卓越－普物教材－理學院長郭艷光主持 Outline 22-1 What Is Physics? 22-2 The Electric Field 22-3 Electric Field Lines 22-4 The Electric Field Due to a Point Charge 22-5 The Electric Field Due to an Electric Dipole 22-6 The Electric Field Due to a Line of Charge 22-7 The Electric Field Due to a Charged Disk 22-8 A Point Charge in an Electric Field 22-9 A Dipole in an Electric Field 彰化師大教學卓越－普物教材－理學院長郭艷光主持

彰化師大教學卓越－普物教材－理學院長郭艷光主持 22-1 What Is Physics? As long as charges are stationary Coulomb’s law described adequately the forces among charges. If the charges are not stationary we must use an alternative approach by introducing the electric field 彰化師大教學卓越－普物教材－理學院長郭艷光主持

彰化師大教學卓越－普物教材－理學院長郭艷光主持 22-2 The Electric Field 彰化師大教學卓越－普物教材－理學院長郭艷光主持

彰化師大教學卓越－普物教材－理學院長郭艷光主持 22-3 Electric Field Lines P electric field line electric field lines P Q 3. Electric field lines extend away from positive charges (where they originate) and towards negative charges (where they terminate). Example 1: Electric field lines of a negative point charge –q 彰化師大教學卓越－普物教材－理學院長郭艷光主持

彰化師大教學卓越－普物教材－理學院長郭艷光主持 22-3 Electric Field Lines 彰化師大教學卓越－普物教材－理學院長郭艷光主持

彰化師大教學卓越－普物教材－理學院長郭艷光主持 22-3 Electric Field Lines The electric field on either side of the plane has a constant magnitude. The electric field vector is perpendicular to the charge plane. The electric field vector points away from the plane. 彰化師大教學卓越－普物教材－理學院長郭艷光主持

22-4 The Electric Field Due to a Point Charge q qo r P 彰化師大教學卓越－普物教材－理學院長郭艷光主持

22-4 The Electric Field Due to a Point Charge 彰化師大教學卓越－普物教材－理學院長郭艷光主持

22-5 The Electric Field Due to an Electric Dipole 彰化師大教學卓越－普物教材－理學院長郭艷光主持

22-6 The Electric Field Due to a Line of Charge dq 彰化師大教學卓越－普物教材－理學院長郭艷光主持

22-7 The Electric Field Due to a Charged Disk 彰化師大教學卓越－普物教材－理學院長郭艷光主持

22-8 A Point Charge in an Electric Field 彰化師大教學卓越－普物教材－理學院長郭艷光主持

22-9 A Dipole in an Electric Field -q +q/2 F+ F- x-axis 彰化師大教學卓越－普物教材－理學院長郭艷光主持

22-9 A Dipole in an Electric Field Potential energy of an electric dipole in a uniform electric field A B  U 180˚ 彰化師大教學卓越－普物教材－理學院長郭艷光主持 (22-15)

22-9 A Dipole in an Electric Field Fig.a Fig.b 彰化師大教學卓越－普物教材－理學院長郭艷光主持 (22-15)

彰化師大教學卓越－普物教材－理學院長郭艷光主持 End of chapter 22! 彰化師大教學卓越－普物教材－理學院長郭艷光主持