1. Electric Potential & Field

2. Connecting Potential and Field

3. Question 1
A proton starts from rest at point A. It then accelerates past point B.
The proton’s kinetic energy at Point B is
250 eV
200 eV
150 eV
100 eV
Answer: D

4. Question 1
A proton starts from rest at point A. It then accelerates past point B.
The proton’s kinetic energy at Point B is
250 eV
200 eV
150 eV
100 eV

5. Question 2
Which set of equipotential surfaces matches this electric field?
Answer: C

6. Question 2
Which set of equipotential surfaces matches this electric field? C.

7. A Conductor in Electrostatic Equilibrium
Properties of a conductor in electrostatic equilibrium:

8. The Electrocardiogram
The electrical activity of cardiac muscle cells makes the beating heart an electric dipole.
A resting nerve cell is polarized; the outside is positive and the inside negative.
Initially, all muscle cells in the heart are polarized, until an electrical impulse from the heart triggers the cells to depolarize, moving ions through the cell wall until the outside becomes negative.
This causes the muscle to contract.
The depolarization of one cell triggers a “wave” of depolarization to spread across the tissues of the heart.

9. The Electrocardiogram
At any instant, a boundary divides the negative charges of depolarized cells from the positive charges of cells that have not yet depolarized in the heart.
This separation of charges creates an electric dipole and produces a dipole electric field and potential.

10. The Electrocardiogram

11. The Electrocardiogram

12. The Electrocardiogram
A measurement of the electric potential of the heart is an invaluable diagnostic tool.
The potential difference in a patient is measured between several pairs of electrodes.
A chart of the potential differences is the electrocardiogram, also called an ECG or an EKG.