Shown below are three different situations. In case A, both point charges are negative. In case B, the left point charge is positive and the right point charge is negative. In case C, the negative charge is uniformly distributed across the circular arc. Rank the three situations by the magnitude of the electric field at point P. (Focus on A vs. B and A vs. C: treat B vs. C as a challenge problem only!)
Figure21.9.1.Three cases with different charges.
A*R*C*S21.9.2.The End of the Line.
A straight wire with one end at \(x = -L\) and the other end at \(x = +L\) has a total charge \(+Q_o\) distributed uniformly. Find the electric field at a point on the \(x\)-axis a distance \(a\) from the center of the wire (where \(a \gt L\)).
Tip.
Sensemaking suggestion: Evaluate your answer in the special case that \(a \gt\gt L\text{.}\)
SubsectionMetacognitive Reflection
Chop-Mutiply-Add is a strategy for calculating the electric field given a continuous charge distribution. You have now completed this process a few times throughout this unit. In your own words, describe how you can use this strategy to determine the electric field of a charge distribution.
