Inductors and inductance and some other stuff

Marioqwe

1. Homework Statement

A certain solenoidal inductor has a magnetic flux of 835 μWb through each loop of its coil when the current flowing through it equals 0.600 A. If the solenoid has 125 loops, what is its inductance?

2. Homework Equations

L = [(N)(magnetic flux)]/I

3. The Attempt at a Solution

L = (8.35e-4)(125)/0.6

L = 0.17H

Is there anything wrong?

1. Homework Statement

A sailboat with an aluminum mast 22.5 m high is sailing eastward along the equator at a speed of 3.66 meters per second. The Earth's magnetic field at the ship's location is 5.50×10−5 T, horizontal and directed due north. What is the induced potential difference between the top and bottom of the mast?

2. Homework Equations

V=LvB

3. The Attempt at a Solution

V = (22.5)(3.66)(5.5e-5)
V = 0.0045T

It marks me wrong

1. Homework Statement

You have three parallel conducting rods. Two of them are very long, and the third is 10.0 m long, with a weight of 36.0 N. You wish to conduct the following levitation demonstration: The two long rods will be placed in a fixed horizontal orientation at the same height, 10.0 cm apart. The third rod is to float above and midway between them, 10.0 cm from each one (from an end view, the three rods will form the vertices of an equilateral triangle). You will arrange to pass the same current I through all three rods, in the same direction through the two "supporting" rods and in the opposite direction through the "levitating" rod. What is the magnitude I of the current that will maintain this astounding configuration?

2. Homework Equations

F = μ0(I1)(I2)(L)/[2(pi)R]

3. The Attempt at a Solution

I'm really confused with this one. I still don't know how to approach it.

I asked my teacher for help and it seems that I'm really dumb I can't even understand this simple problems. He turned me down: "I am giving you the simplest problems in the world, and you fail them on a technicality." I'm having a hard time figuring out some of them.

Any help is appreciated

Thanks

mario

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"Inductors and inductance and some other stuff"

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