A family pet passed away in October 2009. A year after her passing, her owner go

Question

A family pet passed away in October 2009.  A year after her passing, her owner goes outside to investigate the properties of the electric dog fence that was used to contain the dog within the yard.  The electric fence consists of a current carrying wire that carries a current of 12.5 A.

a. From the garage, the owner gets a device used to measure magnetic fields (gaussmeter).  She finds a long straight segment of the electric fence that is running north-south.  The current in this wire is travelling to the North.  She places her neat “magnetic field reader” on the ground, 2 cm to the East of the wire.  What is the magnetic field at this point?  Neglect the Earth’s magnetic field; only consider that produced by the long straight wire. Also, remember that a magnetic field is a vector and has both a magnitude and direction (up from the ground, down, north, south, east or west).

b. The owner goes back to the garage and finds a bag labeled “electrons”.  If an electron is 2 cm to the East of the wire in part a, and travelling to the East with a speed of 2 x 106 m/s, what is the magnetic force exerted on the electron?  Remember, force is a vector and has both a magnitude and direction.

Explanation / Answer

I = 12.5 A
r = 2.0 * 10^-2 m

B = (uo*I)/(2*pi*r)
B = (uo*12.5)/ (2*pi*(2.0*10^-2))
B = 1.25 * 10^-4 T

Direction = Down

(b)
Force on moving Electron,

F = q* (VXB)
F = 1.6*10^-19 * (2*10^6 * 1.25 * 10^-4 ) N
F = 4.0 * 10^-17 N

Direction = North

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.