- #1
binbagsss
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The question is to find the magnetic field at the centre of a current carrying circular loop of radius R, where the current = I
Okay so I'm trying to do this by both Amp's Law and Biot Savarts Law, and I can't get my answers to agree.
First method - Biot Savarts Law:
B=[itex]\frac{I\mu_{0}}{4\pi}[/itex][itex]\int[/itex][itex]\frac{dl X \hat{n}}{n^{2}}[/itex]
n[itex]^{2}[/itex]=R[itex]^{2}[/itex]
dl[itex]X[/itex][itex]\hat{n}[/itex]=dl (as |n|=R is always perpendicular to a given line element dl)
=> B=[itex]\frac{I\mu_{0}}{4\pi}[/itex][itex]\int[/itex][itex]\frac{dl X \hat{n}}{n^{2}}[/itex]=[itex]\frac{I\mu_{0}}{4R^{2}\pi}[/itex][itex]\int[/itex]dl=[itex]\frac{I\mu_{0}}{4R^{2}\pi}[/itex]2R[itex]\pi[/itex]=[itex]\frac{\mu_{0}I}{2R}[/itex]
Second method - Ampere's Law:
[itex]\oint[/itex]B.dl=[itex]\mu_{0}[/itex]I(enclosed)
So B[itex]\oint[/itex]dl=[itex]\mu_{0}[/itex]I
B2[itex]\pi[/itex]R=[itex]\mu_{0}[/itex]I
=> B=[itex]\frac{\mu_{0}I}{2πR}[/itex]
Thanks in advance.
Okay so I'm trying to do this by both Amp's Law and Biot Savarts Law, and I can't get my answers to agree.
First method - Biot Savarts Law:
B=[itex]\frac{I\mu_{0}}{4\pi}[/itex][itex]\int[/itex][itex]\frac{dl X \hat{n}}{n^{2}}[/itex]
n[itex]^{2}[/itex]=R[itex]^{2}[/itex]
dl[itex]X[/itex][itex]\hat{n}[/itex]=dl (as |n|=R is always perpendicular to a given line element dl)
=> B=[itex]\frac{I\mu_{0}}{4\pi}[/itex][itex]\int[/itex][itex]\frac{dl X \hat{n}}{n^{2}}[/itex]=[itex]\frac{I\mu_{0}}{4R^{2}\pi}[/itex][itex]\int[/itex]dl=[itex]\frac{I\mu_{0}}{4R^{2}\pi}[/itex]2R[itex]\pi[/itex]=[itex]\frac{\mu_{0}I}{2R}[/itex]
Second method - Ampere's Law:
[itex]\oint[/itex]B.dl=[itex]\mu_{0}[/itex]I(enclosed)
So B[itex]\oint[/itex]dl=[itex]\mu_{0}[/itex]I
B2[itex]\pi[/itex]R=[itex]\mu_{0}[/itex]I
=> B=[itex]\frac{\mu_{0}I}{2πR}[/itex]
Thanks in advance.