Solved Exercise/Numericals - Electrostatic Energy & Energy Density.
Q.1 Point charges Q 1 = 1 nC, Q 2 = -2 nC and Q 3 = 3 nC and are positioned one at a time and in that order at (0, 0, 0), (1, 0, 0) and (0, 0, -1) respectively. Calculate the energy in the system after each charge is positioned? Ans: Initially the system is assumed to be charge free. The energy required to bring Q 1 into the system is 0 J. After Q 1 : Energy in the system = 0 J The energy required to bring Q 2 into the system is Hence, After Q 2 : Energy in the system = -18 nJ The energy required to bring Q 3 into the system is: W 3 = Q 3 ( V 31 + V 32 ) + Q 2 V 21 Q2. Determine the work necessary to transfer charges Q 1 = 1 mC and Q 2 = -2 mC from infinity to points (-2, 6, 1) and (3, -4, 0) respectively. Ans: No work is done in transferring the first charge Q 1 . However work done to transfer the point charge Q 2 is given as: Q3. A point charge Q is placed at the origin. Calculate the energy stored in region r > a? Ans: ...