Question

Tipler6 28.P.035.

A current integrator measures the current as a function of time and integrates (adds) the current to find the total charge passing through it. (Because I = dq/dt, the integrator calculates the integral of the current or Q = ∫ I dt.) A circular coil that has 300 turns and a radius equal to 4.50 cm is connected to such an instrument. The total resistance of the circuit is 20.0 Ω The plane of the coil is originally aligned perpendicular to Earth's magnetic field at some point. When the coil is rotated through 90° about an axis that is in the plane of the coil a charge of 9.40 µC passes through the current integrator. Calculate the magnitude of Earth's magnetic field at that point.

____ µT

Answer 1

Magnetic field, B = dQ R/N pi r^2

B = (9.4 x 20)/(300 x pi x 0.045^2) = 98.51 uT

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