Question

1. NASA tested a power generation system that involves connecting a small satellite to the space shuttle with a conductive wire several kilometers long. Explain how such a system can generate electricity.
2. The use of high-voltage lines in homes (for example, 600 V or 1,200 V) would reduce energy waste. Why are they not used?
3. What parameters affect the inductance of a coil? Does the inductance of a coil depend on the current in it?
4. How does resistance, capacitive reactance and inductive reactance change, when the frequency in a circuit is increased?
5. Does the phase angle depend on the frequency? What is the phase angle when the inductive reactance is equal to the capacitive reactance?

Answer 1

1- A space tether is a long string or a wire that connects two objects that are in orbit together, An orbiting tether tends to straighten out along a radial line because the force of gravity varies slightly along its length. The pull of gravity is stronger nearest the Earth and weakest furthest away. That means there is a net force on a tether which stretches it and keeps the line taut.As the long wire moves through Earth's magnetic field, the changing magnetic field in the vicinity of the wire induces a current that flows up the tether. If a power supply is added to the tether system and used to drive current in the other direction, an electrodynamic tether can "push" against the Earth's magnetic field to raise the spacecraft's orbit.

2- A voltage that high would be extremely dangerous to have in a home. According to Ohm's Law, current is dependent on voltage (Voltage/Resistance = Current), so if a person were to get an electric shock, a higher voltage would cause more current and a lethal shock.Also, at 1200 volts, there is a possibility of generating high voltage corona, which would be a loss. You would have to insulate internal wiring in the house and motor windings for high voltage, and that would be very expensive.120 or 220 Volts at 60hz was determined to be a compromise on safety and efficiency.

3-The inductance of a circuit depends on the geometry of the current path as well as the magnetic permeability of nearby materials. An inductor is a component consisting of a wire or other conductor shaped to increase the magnetic flux through the circuit, usually in the shape of a coil or helix.Its does not depent on current

4-Capacitive reactance (in ohms) decreases with increasing AC frequency. Conversely, inductive reactance (in ohms) increases with increasing AC frequency. Inductors oppose faster changing currents by producing greater voltage drops; capacitors oppose faster changing voltage drops by allowing greater currents.