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    1. A -3 micro C charge is placed 6 mm away from a -9 micro C charge. What is the potential energy in Joules?

    2. What should be the separation in meters, of one charge of +5 micro C and another of +7 micro C so that the repulsion force is equivalent to 8 N?

    3. Find the electric field intensity in N/C at distance of 40 cm from the center of a -4 micro C charged sphere that has a radius of 20 cm.

    © BrainMass Inc. brainmass.com December 24, 2021, 9:45 pm ad1c9bdddf
    https://brainmass.com/physics/coulombs-law/physics-electrostatics-410836

    SOLUTION This solution is FREE courtesy of BrainMass!

    1. Potential energy of a configuration of two charges Q1 and Q2 separated by a distance r is given by: PE = k Q1Q2/r where k = 1/4Пε0 = 9 x 109

    Substituting Q1 = - 3 μC, Q2 = -9 μC, r = 6 x 10-3 m we get:

    PE = 9 x 109 x (-3 x 10-6)( -9 x 10-6)/ 6 x 10-3 = 40.5 Joule

    2. By Coulomb's law force between two charges Q1 and Q2 separated by a distance r is given by: F = k Q1Q2/r2 where k = 1/4Пε0 = 9 x 109

    Substituting Q1 = +5 μC, Q2 =7 μC, F = 8 N we get:

    8 = 9x109x5x10-6x7x10-6/r2 = 0.315/r2

    r2 = 0.315/8 = 0.039 m

    r = 0.2 m

    3. As the point at which the electric field intensity is to be determined lies out side the sphere and for such a point, the charge on the sphere behaves as if it were concentrated at its center; the electric field intensity is given by:

    E = kQ/r2 = k Q/r2 = 9x109x(-4x10-6)/0.42 = - 2.25x105 N/C

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    © BrainMass Inc. brainmass.com December 24, 2021, 9:45 pm ad1c9bdddf>
    https://brainmass.com/physics/coulombs-law/physics-electrostatics-410836

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