(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

The work done by an external force to move a -8.0μC charge from point a to point b is 8.0 × 10^{-3}J. If the charge initially at rest had 4.0 × 10^{-3}J of kinetic energy ab point b, calculate the potential difference between a and b.

2. Relevant equations

V = W / q

3. The attempt at a solution

Work done per unit charge to move a positive charge from a to b is

V = W / q = 8.0 × 10^{-3}/ -8.0 × 10^{-6}= -1.0 × 10^{3}V

At a E_{k}is 0J and at b it is 4.0 × 10^{-3}J, so

ΔE_{k}= 4.0 × 10^{-3}J.

So work done for each electron to give E_{k}is

V = W / q = 4.0 × 10^{-3}/ -8.0 × 10^{-6}= -0.5 × 10^{3}V

Having E_{k}means that energy is not dissipated. P.d. is the power dissipated per unit current so

(-1.0 × 10^{3}) - (-0.5 × 10^{3}) = -0.5 × 10^{3}V

Is it right way to do it?

Do I need to get rid of negative sign when I calculate the p.d.?

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# Homework Help: Calculate the p.d. between two points

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