Faraday's law and Magnetic Fields

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maksym_slnc
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Homework Statement
A very large loop of metal wire with radius 1 meter is driven with a linearly increasing current at a rate of 200 amps/second . A very small metal wire loop with radius 5 cm is positioned a small distance away with its center on the same axis (the loops are coaxial). The small loop experiences an induced emf of 983nV . What is the separation of the loops in meters?
Relevant Equations
$$
\varepsilon=\oint \overrightarrow{\mathbf{E}} \cdot d \overrightarrow{\mathbf{l}}=-\frac{d \Phi_{\mathrm{m}}}{d t} .
$$
${\mathbf{B}}=\frac{\mu_0 I \hat{\mathbf{j}}}{2 \pi\left(y^2+R^2\right)^{3 / 2}}$
Handwritten-style physics setup: a circular loop of radius R carrying current i, with a small loop of radius r on the axis at distance x, plus given values e = 983 nV, di/dt = 200 A/s, R = 1 m, r = 0.05 m, and x = ?; below are the on-axis Biot-Savart field formula and Faraday's law steps.

I am not really sure which direction i am moving in with this solution
 
Typeset text stating: Using the equation for a magnetic field on an axis derived from a Bio-Savart Law, followed by B = mu0 i / (2 pi (x^2 + R^2)^(3/2)).
Check this formula. Note that that the right-hand side does not have the correct dimensions for magnetic field. Also, check the numerical factors in the equation. For ##x = 0## the formula should reduce to the field at the center of a circular current loop.

Otherwise, your approach looks correct.
 
Last edited:
TSny said:
Check this formula. Note that that the right-hand side does not have the correct dimensions for magnetic field. Also, check the numerical factors in the equation. For ##x = 0## the formula should reduce to the field at the center of a circular current loop.

Otherwise, your approach looks correct.
Oh, thanks a lot, it was a vector form, but without the i hat. Correct expression was this one.
Boxed equation: B = μ0iR² divided by 2(R² + x²) raised to the power 3/2, the axial magnetic field of a current loop at distance x from its centre.
 
maksym_slnc said:
Oh, thanks a lot, it was a vector form, but without the i hat. Correct expression was this one.View attachment 325234
Ok. You should get a reasonable answer now.