# quipotential lines

#### Kussemek

##### Senior Member
7+ Year Member
15+ Year Member
why is is that they cant cross, is it the same reason that field lines cant cross?

#### Daichi Katase

##### Senior Member
10+ Year Member
5+ Year Member
Yeah basically....Equipontential lines mean that the poteinal anywhere on that line is the same. If two equipotential lines crossed....they wouldn't be equipontential lines. You know what i mean?

...well unless you can warp space and time. Then all bets are off.

#### Shrike

##### Lanius examinatianus
10+ Year Member
If you mean gravitational equipotential lines, they can't cross. The reason is actually kind of confusing, involving higher math than you are expected to know.

Note to chubby: Space-time is warped by gravity, in many physicists' eyes; it is actually the direction of the warping's being the same everywhere that provides the above result. Equipotential lines conceivably could cross, if the characteristics of the field were different, but the crossing lines would have to have identical potentials to each other, by definition -- I think this last part is what you meant. And no, no, you don't have to know any of this.

On the other hand, electrical equipotential lines can cross each other. For proof, consider the simplest such case that I can think of: an electrostatic quadrupole. Locate point charges of +1 at 2-d coordinates (1,1) and (-1,-1), and charges of -1 at (1,-1) and (-1,1). Now the x- and y-axes are each equipotential lines (with potential = 0), and they cross at the origin.

The reason for the difference is, as I said, mathematically complex, and you don't need to know it, but I thought I'd address the orginal question lest anyone become confused upon arriving at electrostatics.

Shrike

#### Turkeyman

##### Trickster Poultry
10+ Year Member
5+ Year Member
Shrike rocks!

But hey shrike are you a robot?

#### Shrike

##### Lanius examinatianus
10+ Year Member
Turkeyman said:
Shrike rocks!

But hey shrike are you a robot?
<beep> that - does - not - com - pute <beep>

Thank you, sir.

Nope, not a robot, just your average, everyday kinda guy who reads textbooks in sciences he's never studied, for fun, and then appears out of nowhere to save the day for professional-school aspirants. Think Bruce Wayne, only without the money or the charm. Or the faithful sidekick. Or the mask and cape. OK, not Bruce Wayne. Actually, robot is sounding better and better.