1(b) & 1(c)
We set Ez = 0 which means setting the green and red terms above equal to each other. Then you solve the resulting equation for D.
We set Ez = 0 which means setting the green and red terms above equal to each other. Then you solve the resulting equation for D.
1(d)
The peak positive value of Ez will occur at D=0 when you are directly below the two charges. I mention this here because it may be a little difficult to see where it emerges from the work below.
In this last part of the question we'll differentiate the expression for Ez with respect to D and set the result equal to 0.
The peak positive value of Ez will occur at D=0 when you are directly below the two charges. I mention this here because it may be a little difficult to see where it emerges from the work below.
In this last part of the question we'll differentiate the expression for Ez with respect to D and set the result equal to 0.
There are some common factors that
we can bring out of the brackets
We get rid of all the terms out
in front of the brackets except for D. D = 0
is a solution to the equation. And note that
solution does not depend on the values of HN
and HP
The last part of the problem is to find the value of D that makes the bracketed term = 0.
2(a)
This problem was largely worked out in class.
Resistivity is basically an electrical property of a material. The resistance depends on the resistivity but also the size and shape of an object and how wires are connected to it.
We worked out three possibilities in class (R is resistance in ohms, Re is resistivity in ohm m)
We can substitute in for Re (7 x 10-6 ohm m) to obtain the resistance for two of the three cases above.
2(b)
Clearly the resistance does depend on where you connect the leads.
3
We use the example in the class notes as a guide. This example is much simpler largely because the E field in the space between the two plates is constant (Ez = V/d)
The last part of the problem is to find the value of D that makes the bracketed term = 0.
2(a)
This problem was largely worked out in class.
Resistivity is basically an electrical property of a material. The resistance depends on the resistivity but also the size and shape of an object and how wires are connected to it.
We worked out three possibilities in class (R is resistance in ohms, Re is resistivity in ohm m)
We can substitute in for Re (7 x 10-6 ohm m) to obtain the resistance for two of the three cases above.
2(b)
Clearly the resistance does depend on where you connect the leads.
3
We use the example in the class notes as a guide. This example is much simpler largely because the E field in the space between the two plates is constant (Ez = V/d)