Two stiff, 50-cm-long, parallel wires are connected at the ends by metal springs. Each spring has an unstretched length of 5.0 cm and a spring constant of 0.025 N/m. The wires push each other apart when a current travels around the loop. How much current is required to stretch the springs to lengths of 6.0 cm?

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 n