An electron is initially moving to the right when it enters a uniform electric field directed upwards. Which trajectory shown below will the electron follow? (W, X, Y, Z)

Two equal positive charges are held in place at a fixed distance. If you put a third positive charge midway between these two charges, its electrical potential energy of the system (relative to infinity) is zero because the electrical forces on the third charge due to the two fixed charges just balance each other.  

In a certain region, the electric potential due to a charge distribution is given by the equation V(x,y,z) = 3x2y2 + yz3 – 2z3x, where x, y, and z are measured in meters and V is in volts. Calculate the magnitude of the electric field vector at the position (x,y,z) = (1.0, 1.0, 1.0). 

The magnitude of the Poynting vector of a planar electromagnetic wave has an average value of 0.939 W/m2. The wave is incident upon a rectangular area, 1.5 m by 2.0 m, at right angles.  (a) How much total electromagnetic energy falls on the area over 1.0 minute?     (b) What are the amplitudes of the electric and magnetic fields of this wave?  E: B:

What is the current through the inner (lone) 1.0kΩ resistors in the RC circuit below at time 0.25ms after the switch is closed? The potential across the capacitors is initially 5.0V.

An oil-water mixture works as an insecticidal spray against mosquitoes and other insects because it _____.

A 200-loop coil of cross-sectional area 8.5 cm2 lies in the plane of the page. An external magnetic field of 0.060 T is directed out of the plane of the page. The external field decreases to 0.020 T in 12 milliseconds.   (a) What is the magnitude of the change in the external magnetic flux enclosed by the coil?   (b) What is the magnitude of the average voltage induced in the coil as the external flux is changing?      

An anthropologist discovers the fossilized heart of an extinct animal. The evidence indicates that the organism’s heart was large, was well-formed, and had four chambers, with no connection between the right and left sides. A reasonable conclusion supported by these observations is that the _____.

A thin, circular disk of radius 30.0 cm is oriented in the yz-plane with its center at the origin. The disk carries a total charge of +3.00 μC distributed uniformly over its surface. Below the xy-plane at z= -10.0cm (centered at (x,y,z) = (15.0, 0.0, -10.0)) lies a ring in a plane parallel xy with total charge –2.00µC and radius 15.0cm. Calculate the electric field at the point (15.0, 0.0, 0.0) and report your answer in component form.  (Enter your units in the last box.)

The average axial length of the eye is: