i need help understandings these concepts. i just dont get the relationships between things like force, magnetic field (B), velocity of a particle (eg a proton), EMF, induction of a field, etc...(adsbygoogle = window.adsbygoogle || []).push({});

can someone please get me started on these problems and help me understand the concepts and equations.

1) a proton falls through a potential difference of 10^5 volts - what speed will it have if it starts from rest?

2) A wire 30 m long moves at 2 m/s perpendicularly through a field of magnetic induction 1 N/Am. a) what EMF is induced in the wire? b) the total resistance of the circuit of which the wire is part of is 15 ohms - what current flows?

3) Double-ionized helium atoms (alpha particles) are traveling at right angles to a magnetic field at a speed of 4.0 x 10^4 m/s and the induction of the field is 5.0 x 10^-2 N/Am. what force acts on each particle?

4) An oil drop weighs 9.0 x 10^-15 N. It is suspended in an electric field of 2 x 10^4 N/coul. a) what is the charge on the oil drop? b) how many excess electrons does it carry?

5) what energy is given to an electron to transfer it across a difference in potential of 4.0 x 10^5 volts?

now i dont expect the answers of course, but i really need some help getting started and just understanding all the different relationships between the terms and concepts.

and did i do this one right:

A wire weighing .5 N/m is exposed to a magnetic field of strength .25 N/Am for a distance of 1.3 m. What current must flow in the wire to suspend it in the field?

I used the equation B = (u x I)/(2pi x d)

sorry i dont know how to use the symbols but pi is obviously pi (3.14) and u is suppose to be that constant 4pi x 10^-7). i plugged all of those in and solved for I to get 1.625 x 10^6 A.

although im not sure what to do with that .5 N/m (and how is that a weight anyways? isnt weight in N?)

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# Help with magnetism/electromagnetic inducion/ac circuits

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