1.  The Earth has a magnetic field with a vertical component of 4.2 x 10^-5 T pointed straight down at the ground.  If Fox Mulder and Dana Scully are investigating the world's largest slot car racing track, with an effective area of 142,000 square meters, what is the flux through the set?

2.  If Fox turns the set about a horizontal axis (parallel with the Earth's surface) such that the flux changes by -2 webers in 10 seconds, what is the induced EMF in the slot car track?

3.  If the car track has an internal resistance of 30 ohms, it comes with an AC / DC converter (and an AC / DC CD), and Dana reads in the instructions that the set needs to receive at least 12 Amps of current, will the set run be able to run by itself?

1.  Flux is equal to the exposed area of the surface x the strength of the magnetic field x the cosine of the angle of incidence between the surface and the lines of the magnetic field.

Flux = BA cos X

Therefore, the flux through the slot car track is:
(4.2 x 10^-5)(142000)(1) = 5.964 Wb

2.  Faraday's Law of electromagnetic induction states that the EMF induced is equal to the rate of change in the flux through the object.

EMF = -(change in flux)/(time interval)

Therefore, the induced EMF through the track is:
(-1)(-2)/(10) = 0.5 V

3.  For this question, we go back to electricity and use Ohm's Law, which states that the voltage in a circuit is equal to the current multiplied by the resistance.

V = IR

Therefore, the current in the track is:
(0.5) = (I)(30) >>> I = (.5)/(30) = .017 A

No, this is nowhere near enough current.  Sorry, Fox.

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