Electric Potential & Field

Connecting Potential and Field

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

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

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

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

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

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.

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.

The Electrocardiogram

The Electrocardiogram

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.