Electric Field of a Segment of Charge

Moelter Electromagnetism

Electric field of a segment of charge

Field due to chunks

A thin rod of charge is on the x-axis between -L and L with charge density, .

·  On each diagram, using three arrows (), indicate the electric field at the dot due to each of the striped chunks. (You should imagine the positive test charge is at the dot.)

·  Also indicate, using a double arrow (), the sum of the three electric fields at each dot.

Total field

A thin rod of charge is on the x-axis between -L and L with charge density as indicated.

Now, using many arrows at many points in space around the rod, indicate the total electric field for the charge density indicated. (Hint: Think about how the charge is distributed.)

Moelter Electromagnetism

Velocity selector

In the dotted region there is a constant electric field, E0, upward and a constant magnetic field, B0, out of the page. A particle of mass m and charge q (>0) is moving to the right at speed v0.

What will happen when the particle enters the field region?

Observe what happens in the simulation. On the figure above, using a dashed line, indicate the trajectory of the particle. Leaving the fields the same, how should we change the initial speed of the particle so that it passes through the field region undeflected?

Mjm 8/1/02 HandoutFieldSelector Page 2 of 2