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A solenoid is made from a copper wire that is 15 m long and has a radius of 1.6 mm. The resistivity of copper is 1.68 x 10-8 Ωm. To form the solenoid, the copper wire is tightly wrapped around a tube that is 0.35 m long and has a diameter of 2.5 cm. The solenoid is connected to a power source which supplies an emf of 2.5 V. Find the magnitude of the magnetic field through the center of this solenoid

Respuesta :

Answer:

The magnitude of the magnetic field through the center of this solenoid is 0.0568 T.

Explanation:

Given that,

Length = 15 m

Radius r₁ = 1.6 mm

Resistivity of copper[tex]\rho=1.68\times10^{-8}\ \Omega m[/tex]

Radius [tex]r_{2} =\dfrac{2.5}{2}=1.25\ cm[/tex]

emf = 2.5 V

Length of tube = 0.35 m

We need to calculate the area of cross section

[tex]A = \pi r_{1}^2[/tex]

[tex]A=\pi\times(1.6\times10^{-3})^2[/tex]

[tex]A=0.000008042\ m^2[/tex]

[tex]A=8.038\times10^{-6}\ m^2[/tex]

We need to calculate the resistance

Using formula of resistivity

[tex]R = \dfrac{\rho l}{A}[/tex]

Put the value into the formula

[tex]R=\dfrac{1.68\times10^{-8}\times15}{8.038\times10^{-6}}[/tex]

[tex]R=0.03135\ \Omega[/tex]

We need to calculate the current

Using formula of current

[tex]I=\dfrac{\epsilon}{R}[/tex]

Where, [tex]\epsilon[/tex] = emf

Put the value into the formula

[tex]I=\dfrac{2.5}{0.03135}[/tex]

[tex]I=79.745\ A[/tex]

We need to calculate the number of turns per unit length

Using formula of number of turns

[tex]N=\dfrac{l}{2\pi r_{2}}[/tex]

[tex]N=\dfrac{15}{2\pi\times1.25\times10^{-2}}[/tex]

[tex]N=190.98[/tex]

[tex]n=\dfrac{N}{l}[/tex]

[tex]n=\dfrac{190.98}{0.35}[/tex]

[tex]n=545.65\ turns/m[/tex]

We need to calculate the magnetic field

Using formula of magnetic field

[tex]B=\mu_{0}nI[/tex]

[tex]B=4\pi\times10^{-7}\times545.65\times79.745[/tex]

[tex]B=0.0568\ T[/tex]

Hence, The magnitude of the magnetic field through the center of this solenoid is 0.0568 T.