A long wire carries a current of 3.0A along the central axis of a long solenoid (radius=3.0cm, n=900 turns per meter, current=30.0mA). What is the magnitude of the magnetic field at a point 2.0cm from the axis of the solenoid (neglecting any end effects)?

Respuesta :

Answer:

The magnitude of the magnetic field is [tex]B=3.39*10^{-3} T[/tex]

Explanation:

current:[tex]I=3.0A[/tex]

radius: [tex]0.03m[/tex]

[tex]n=900 turns/m[/tex]

[tex]u_{0} =4\pi *10^{-7}Tm/A[/tex]

The find number of turns:

[tex]n=\frac{turn }{length } \\turn=n*length\\turn=(900turns/m)*(0.02m)\\turn=18 turns[/tex]

so the solenoid has 18 turns

Now to find magnetic field of the solenoid:

[tex]B=u_{0} nI\\B=(4\pi *10^{-7}Tm/A)*(900turns/m)*(3.0A)\\B=3.39*10^{-3} T[/tex]

Answer:

B = 63.93 μT

Explanation:

Current carried by the wire, I₁ = 3.0 A

Number of turns, n = 900 turns/ meter

Radius of the solenoid, R = 3 cm = 0.03 m

r = 2 cm = 0.02 m

Current due to the solenoid, I₂ = 30 mA = 0.03 A

The magnetic field is due to the current carrying conductor and the solenoid

Magnetic field due to the current carrying conductor:

[tex]B_{1} = \frac{\mu I_{1} }{2\pi r} \\B_{1} = \frac{\mu 3}{2\pi *0.02}\\ B_{1} = \frac{\mu 3}{0.04\pi }[/tex]

Magnetic field due to the solenoid:

[tex]B_{2} = \mu N I_{2} \\B_{2} = \mu * 900 * 0.03\\B_{2} = 27 \mu[/tex]

Add B₁ and B₂ together

B = B₁ and B₂

[tex]B = \frac{\mu 3}{0.04\pi } + 27 \mu\\B = 50.87 \mu\\\mu = 4\pi * 10^{-7} \\B = 50.87 * (4\pi * 10^{-7})\\B = 63.93 * 10^{-6} T\\B = 63.93 \mu T[/tex]