Question

A +40 μC point charge is placed 54 cm from an identical +40 μC charge.

How much work would be required for an external force to move a +0.40 μC test charge from a point midway between them to a point 11 cm closer to either of the charges?

Answer 1

Solution +40MC c +0.4040 + 40 uc A +11 cm 54cm Potential difference at the midpoint d'is zero because both charges are equal and cancel out each other. potential due to Potential at 'O'due to point charge at A is given by VA = 1 Q - 40x156 496 T ATTE (27x152) Potential at 'o' due to point charge at 'B' is given by vost o I a. I to. 4TTE. (27x102) 4T & r VA - VB at '0' - VA V = 0 Potential difference at is given by - 411E (27-118102 A = 1 40x156 novo 9X100 40x156 168102 V₂ = - 1 4TTE 40x106 (27+0 2 = 2 9X10 x 40 x 106 38x102 van het=9x109 x 40 xto" [ Toxo? - Flexib 27 = 9x1oºx40x156 [76-47X102 = 3.68107 [76 - 13]

- Vo = 3.6x107 [to - 1 - 3-6X107 x 0.0361 = 1.30X106 volt VA V The workdone will be positive to go from midway o' to 'C' and given by W = q (VA-Vel) = 0.40X106(130 X 166) W = 0.52 Joules. The work required to move Charge from midway 'o' to a point " c. is given by W= 0.52 Joules