AY Honors/Electricity/Answer Key
Electricity
Explain and illustrate an experiment by which the laws of electrical attraction and repulsion are shown.
Explain the difference between direct and alternating current, and demonstrate the uses to which each is adapted. Give a method of determining which kind flows in a given circuit.
Electricity in a direct current (DC) circuit flows in only one direction. In an alternating current (AC) circuit, the direction of current flow reverses at a regular rate. Similarly, the voltage in a DC circuit remains constant, while it continuously varies in an AC circuit.
Batteries are capable of storing DC voltage only - they cannot store AC voltage. Most electronic circuitry runs on DC, and electronic appliances that run on AC power usually convert it to DC before it can be used. The advantage AC has over DC is that it can be transmitted over long distances with less loss than a DC circuit providing an equivalent amount of power.
AC circuitry produces a constantly varying magnetic field, and a constantly varying magnetic field will induce a current in an adjacent conductor. The induced current can be measured with a current meter. DC circuitry will only induce a current when a sudden change in the circuit takes place, such as powering it on. The induced current will "spike" briefly and then decay to zero.
