Shock Value B

[andrewwski]

Not a thing.

[--[Grand]--]

Could you provide an example for internal resistence in a problem?

There are some great resources we've put up on the official Shock Value website that might help you:
http://soinc.org/shock_value_b

In particular, the ibiblio book has a section on internal battery resistance: http://www.ibiblio.org/kuphaldt/electri ... DC_11.html

Thank you.

[JSGandora]

Do any of you think that studying great figures in DC Circuit Theory would be worth it? We had a tiebreaker question that asked for the first and last name of the dude who figured out the relationship between voltage, current, and resistance. It's obviously Ohm but my partner and I were freaking out because we didn't know his first name.

[fleet130]

I didn't know Mr. Ohm's first name either so I started calling him "George". For years I talked about our good friend "George Ohm" when discussing electronics. Finally, one day I decided is didn't show proper respect to arbitrarily give him a first name, so I looked it up. Much to my surprise, Mr. Ohm's first name was "Georg".

[--[Grand]--]

Does anyone know some properties of an electric field? Or maybe a resource for it?
Could anyone help me with this question?
1.Which of the following is true for the direction of an electric field?
a.It is same as the direction of the force exerted on a negative test charge.
b.It is opposite to the direction of the force exerted on a positive test charge.
c.It is same as the direction of the force exerted on a positive test charge.
d.It is opposite to the direction of the forced on a neutral test charge.

[andrewwski]

C. The direction of an electric field is the same as the direction of the force it exerts on a positively charged particle.

If you didn't know that, you should be able to make a pretty good guess from the structure of the question. Notice that A and B are actually the same answer - opposite the direction of a positive charge is the same direction as a negative charge. Since there is only one answer, those two must be incorrect. And D is obviously incorrect, since an electric field will not affect a neutral particle

As an equation, electric field E is equal to force divided by charge, or E=F/q, where F is the force on the particle and q is the charge of the particle. Since we know that positively charged particles have a positive sign, we can tell that both sides of the equation are positive, thus, the direction is the same.

If the particle were negatively charged, q would be negative, and the LHS would have a different sign than the RHS, thus, the direction of the field would be opposite that of the force.

[tuftedtitmouse12]

sorry to ask, but i was just wondering if any of you guys kno any links with any of the topics we have to kno?? i mean, like this is our first year in shock value and were kinda new to this...we kinda have to circuit thing down, but we need to find maybe a few more bits of stuff to kno....

[robotman]

Well I would start with the Shock Value Wiki and than the Test Exchange Wiki For tests

[tuftedtitmouse12]

Well I would start with the Shock Value Wiki and than the Test Exchange Wiki For tests

ok..thanks...btw, purplepeopleeater recommended you to me for shock value stuff....just saying...

[--[Grand]--]

C. The direction of an electric field is the same as the direction of the force it exerts on a positively charged particle.

If you didn't know that, you should be able to make a pretty good guess from the structure of the question. Notice that A and B are actually the same answer - opposite the direction of a positive charge is the same direction as a negative charge. Since there is only one answer, those two must be incorrect. And D is obviously incorrect, since an electric field will not affect a neutral particle

As an equation, electric field E is equal to force divided by charge, or E=F/q, where F is the force on the particle and q is the charge of the particle. Since we know that positively charged particles have a positive sign, we can tell that both sides of the equation are positive, thus, the direction is the same.

If the particle were negatively charged, q would be negative, and the LHS would have a different sign than the RHS, thus, the direction of the field would be opposite that of the force.

Ohh I see. Thanks Now that I think about it...C would have been the best guess.

Another question:
Three charges 4q, Q, and q are placed in a straight line of length r at points O, r/2, and r respectively as shown in the diagram. Find the value of Q that would make the force on q zero. There's also a diagram, but I don't know how to type it out. Could you explain/tell me if I need the diagram or not?