(a) Write the complete reaction equation for electron capture by 15 O . (b) Calculate the energy released. Data from the appendices and the periodic table may be needed for these problems.

Lecture 7 Potential from a distribution of charges X V = 1 qi 4⇡✏0 ri §Smooth distribution 1 X qi 1 Z ⇢ V = = dV 4⇡✏0 i ri 4⇡✏ 0 r § of point charges is usually much simpler thanup calculating the electric field •It’s a scalar Electric Potential from Two Oppositely Charged Point Charges §The electric field lines from two oppositely charge point charges are a little more complicated §The electric field lines originate on the positive charge and terminate on the negative charge §The equipotential lines are always perpendicular to the electric field lines §The red lines represent positive electric potential §The blue lines represent negative electric potential §Close to each charge, the equipotential lines resemble those from a point charge 22 Electric Potential from Two Identical Point Charges §The electric field lines from two identical point charges are also complicated §The electric field lines originate on the positive charge and terminate at infinity § Again, the equipotential lines are always perpendicular to the electric field lines §There are only positive potentials §Close to each charge, the equipotential lines resemble those from a point charge 23 Example: Superposition of Electric