- #1
Manchot
- 473
- 4
I have a question regarding charged spheres and voltage measurements. I've talked to my physics professor about it, and he wasn't quite sure of the answer (although to be fair, I asked briefly at the end of class.)
Imagine that you had a spherical shell, charged to a high potential (for the sake of argument, we'll say 100 kV). Now, in that shell, there's a small hole, where a small, insulated copper wire is piped in. At the other end of the wire, which is very far away, there is a constant 12V DC source, and the positive terminal is connected to the wire. Here's my question. If one was to measure the voltage of the wire with respect to the negative terminal inside the spherical shell, what would one read? Furthermore, if a capacitor was placed inside the sphere and attached to the wire's end, would it charge up (i.e., would current flow through the wire)? I've attached a picture for clarification.
It seems to me that there are two conflicting ideas here. First, I know that the E-field inside the shell is zero. However, just outside the sphere, it is relatively high. If I was to draw a voltage vs distance from center graph, at infinity, the voltage would equal 12V. At r, the radius of the sphere, it would equal 100kV, having slowly increased, and inside the sphere, it would drop to zero. So, I guess my question is: would positive holes be able to overcome the large increase in potential in order to decrease their overall potential (from 12V to 0V)? That is, can holes (or electrons, for that matter), act like water in a siphon?
Imagine that you had a spherical shell, charged to a high potential (for the sake of argument, we'll say 100 kV). Now, in that shell, there's a small hole, where a small, insulated copper wire is piped in. At the other end of the wire, which is very far away, there is a constant 12V DC source, and the positive terminal is connected to the wire. Here's my question. If one was to measure the voltage of the wire with respect to the negative terminal inside the spherical shell, what would one read? Furthermore, if a capacitor was placed inside the sphere and attached to the wire's end, would it charge up (i.e., would current flow through the wire)? I've attached a picture for clarification.
It seems to me that there are two conflicting ideas here. First, I know that the E-field inside the shell is zero. However, just outside the sphere, it is relatively high. If I was to draw a voltage vs distance from center graph, at infinity, the voltage would equal 12V. At r, the radius of the sphere, it would equal 100kV, having slowly increased, and inside the sphere, it would drop to zero. So, I guess my question is: would positive holes be able to overcome the large increase in potential in order to decrease their overall potential (from 12V to 0V)? That is, can holes (or electrons, for that matter), act like water in a siphon?