Question

A very long, straight wire carries a current of 15.5 A out of the screen. An electron outside the wire is 1.13 cm to the right of the central axis of the wire and is moving with a speed of 5.45×106 m/s. Find the magnitude of the magnetic force on the electron if it is moving directly away from the wire (i.e., rightward). Tries 0/5 Find the magnitude of the force on the electron if it is moving parallel to the wire in the direction of the current (i.e., out of the screen). Tries 0/5 Find the magnitude of the force on the electron if it is moving upward.

Answer 1

Here,

I = 15.5 A

d = 1.13 cm = 0.0113 m

for the magnetic field

magnetic field at the location , B = u0 * I/(2pi * d)

B = 4pi *10^-7 * 15.5/(2pi * 0.0113)

B = 2.74 *10^-4 T

the magnetic field is 2.74 *10^-4 T

NOw, for the case 1 ,

when the electron if it is moving directly away from the wire

the force on the electron is ZERO

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magnitude of the force on the electron if it is moving parallel to the wire in the direction of the current

magnitude of force = 2.74 *10^-4 * 5.45 *10^6 * 1.602 *10^-19

magnitude of force = 2.4 * 10^-16 N

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the magnitude of the force on the electron if it is moving upward.

the force on the electron is ZERO