Dielectric boundary conditions. At the interface between two dielectric materials with dielectric constants ε1 and ε2, the electric field intensity everywhere in material 1, � 1, has magnitude 1 and makes an angle α1 with the normal to the interface between the materials. There is a charge with surface charge density rhos sandwiched between the two materials. Determine the charge density rhos such that the electrical field intensity in material 2, �2 , is exactly equal to � 1.

Astone is thrown with a speed v0 and returns to earth, as the drawing shows. ignore friction and air resistance, and consider the initial and final locations of the stone. which one of the following correctly describes the change δpe in the gravitational potential energy and the change δke in the kinetic energy of the stone as it moves from its initial to its final location? options a.δpe = 0 j and δke = 0 j b.δpe is positive and δke is negative c.δpe = 0 j and δke is positive d.δpe is negative and δke is positive e.δpe = 0 j and δke is negative