SP ’11, TEST 1 |
1. (35 points) A charge of magnitude q = 4.00x10 -3 C is placed at each
corner of a square with side a = 0.100 m. The charges at the upper left and lower right corners
are negative. The charges at the upper
right and lower left corners are positive.
(b) (15 points) direction of the net force on the charge at the lower right corner ? ------------------------------------------------------------------ (b) (20 points) what is the magnitude E ------------------------------------------------------- 3. (35 points ) An
electron starts from rest 30.00 cm away from a fixed point charge with Q =
+0.100 µC . 4. (11 points)
Below, a rectangular solid is
made of carbon with sides 2.00 cm, 8.00 cm and 4.00 cm lying on the x, y and x axes in that order.
The resistivity is ρ = 3.10x10-5 ohm-m. Current is allowed to pass in the x
direction, y-direction
or z-direction only. For each possible current direction, you
connect wires from a battery across the two opposite faces
perpendicular to the current. (b)
(3 points) y direction, (c)
(3 points) z direction. (d)
(1 points) Which current is the largest, current in x-direction, current in
y-direction or current in z-direction? Explain. ----------------------------------------------------------------------------------- 5. (35 points) A special extension cord has length L =
5.00 m and rectangular cross-section given by width w = 0.100 cm and small length = 0.070 cm .
Between the ends of the cord there is a voltage difference given by V+ - V-
. The current I = 12.0 (A) . See diagram below . (a) (20 points) What is the voltage difference V+ - V- ? (b)
(10 points) What is the rate of heat generation (in
Watts) in the cord? |