Your friend wants to be magician and intends to use earth’s magnetic field to suspend a current-carrying wire above the stage. he asks you to estimate the minimum current needed to suspend the wire just above earth’s surface at the equator (where earth’s magnetic field is horizontal). assume the wire has a mass of 10 g, and length of 1.0 m. would you advise him to proceed with his plans for this act?

Explanation:

Under this  condition, . In order to suspend the wire, this magnetic force would  have to be equal in magnitude to the gravitational force exerted by Earth on the  wire the maximum force at angle

F=ILxB

Now to the suspend the wire so use the maximum force and solve to the current knowing the magnetic field of the earth

∑Fy=0

Solve to I current

I suggest do an toher act is really risk that current for an act

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation: