OK first off I'd like to thank Warr for helping me with one problem(adsbygoogle = window.adsbygoogle || []).push({});

again thanks a lot

Okay now to business I have an ISU (Independent Study Unit) due this thursday and I'm pretty much all done, but it would be great if you guys could just look over it for any mistakes and or advices. ISU is 6 quetions, one I already posted so here we go:

1.A charge of 2.730 C is placed at each corner of an equiolateral triangle 1.520 m on a side. Direction of force and magnitude on each charge?

Solution: ok in all cases the magnitude of the force will be the same - because its an equiolateral triangle. to find it I used

F=k x q1q2/r^2= 9.00x10^9 x 7.453^2/2.310^2=2.89x10^10 I got directions as well 2 for each charge -- compass ones -- N30W and NW, N30E and NE, and S30W and S30W

This one was easy

2.Two 1.5 V batteries are connected in series to a bulb with resistance of 10 Ohm . How many electrons leaveeach batteryper minute?

R=V/I 10=3V/I I=o.3A

Q=It Q=0.3A x 60s=18C

Q=Ne N=Q/e=18C / 1.6x10^-19 = 1.125x10^20 -- for 2 batteries

But here is where I get lost/confused -- if the batteries are in series then say 2 electrons leave first battery, go into second one and then second has it's own 2 electrons leaving plus 2 that came into it, right or wrong???

4. A transformer has 78 turns in primary and 158 in secondary. What kind of transformer is this and if it is 100% efficient, by what factor does it change the current.

Okya this is obviously a step up transformer andits factor is Vs/Vp=Ns/Np Vs/Vp=158/78 Vs/Vp=2.03

So by the factor of 2

5. This is the one I'm having major trouble with -- Over long distances high-power transition lines split into four parallel cables. Given that these four cables are parallel and carry current in the same direction, do they repel ir attract one another? Explain your reasoning clearly.

Okay this is the scoop -- my textbook just says that 2 parallel wire with current in same direction attract. They just do. Thats what book says. I think that they would actually repel but I really can't explain so any sort of help on this bugger will be much appreciated.

6. What's the mass of 100mC of electrons ( m being the symbol for micro)

100x10^-6C= 10^-4C

1C=6.24x10^18e

10^-4C= 6.24x10^15e

total mass= (6.24x10^15e) x mass of 1 e

= (6.24x10^15e) x (9.11x10^-31 kg)

= 5.68x10^-15 kg

Okay so that was it and please please please can you look into it and pooint out mistakes. I would've done this earlier but I only came over the site yesterday.

Thank you

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# Homework Help: More on electromagnetism

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