Concept explainers
(a)
The resistance of the solenoid, if it is made from a 100 m copper wire with cross-sectional area
(b)
The inductance of the solenoid, if it is made from a 100 m copper wire with cross-sectional area
(c)
The frequency of the alternating current at which the inductive reactance of the solenoid is equal to its resistance, if it is made from a 100 m copper wire with cross-sectional area
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College Physics
- When a wire carries an AC current with a known frequency, you can use a Rogowski coil to determine the amplitude Imax of the current without disconnecting the wire to shunt the current through a meter. The Rogowski coil, shown in Figure P23.8, simply clips around the wire. It consists of a toroidal conductor wrapped around a circular return cord. Let n represent the number of turns in the toroid per unit distance along it. Let A represent the cross-sectional area of the toroid. Let I(t) = Imax sin t represent the current to be measured. (a) Show that the amplitude of the emf induced in the Rogowski coil is Emax=0nAImax. (b) Explain why the wire carrying the unknown current need not be at the center of the Rogowski coil and why the coil will not respond to nearby currents that it does not enclose. Figure P23.8arrow_forwardAn AC source operating at 60. Hz with a maximum voltage of 170 V is connected in series with a resistor (R = 1.2 k) and an inductor (L = 2.8 H). (a) What is the maximum value of the current in the circuit? (b) What are the maximum values of the potential difference across the resistor and the inductor? (c) When the current is at a maximum, what are the magnitudes of the potential differences across the resistor, the inductor, and the AC source? (d) When the current is zero, what are the magnitudes of the potential difference across the resistor, the inductor, and the AC source?arrow_forwardA person is working near the secondary of a transformer as shown in Figure P32.31. The primary voltage is 120 V at 60.0 Hz. The secondary voltage is 5 000 V. The capacitance Cs, which is the stray capacitance between the hand and the secondary winding, is 20.0 pF. Assuming the person has a body resistance to ground of Rb = 50.0 k, determine the rms voltage across the body. Suggestion: Model the secondary of the transformer as an AC source. Figure P32.31arrow_forward
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