Electrical Engineering is part of Engineering and holds 3,646 questions with answers, free to read and with no account needed.
Attempt each question before revealing the answer, and keep a note of the ones you get wrong — those are the topics worth reading about properly. If an answer looks wrong, there is a link to report it on every question.
Answer: A. a long line
Power transmission lines measuring three hundred ten kilometers exceed the two hundred fifty kilometer threshold. Electrical transmission engineering classifies lines over two hundred fifty kilometers explicitly as long...
Answer: A. suspension insulators
High-voltage electrical power transmission lines require robust insulation systems to prevent dangerous flashover faults. Suspension insulators consist of multiple porcelain or glass discs linked together in flexible ver...
Answer: A. 31.25 percent of copper
A 3-wire DC distribution system achieves remarkable copper savings compared to standard 2-wire setups. Mathematical derivation shows that a 3-wire distributor consumes precisely 31.25 percent of equivalent copper. Adding...
Answer: B. Isolators
Isolators are mechanical disconnect switches designed strictly to operate when no current is flowing in the circuit. Because they are never opened under load, they do not need continuous current rating specifications for...
Answer: D. Current, voltage, frequency and short time current
Bus-bars must be rated comprehensively for continuous current, system voltage class, and operating frequency. They also require a short-time current rating to withstand mechanical forces during severe fault conditions. I...
Answer: A. series wound generator
An electrical booster is essentially a series-wound DC generator inserted directly into a distribution feeder line. The series field winding carries the full load current, causing generated voltage to increase with load...
Answer: B. short-circuit current of the system is increased
Maintaining a constant voltage across transmission lines requires reducing overall system impedance significantly. Lower system impedance directly leads to massive increases in potential short-circuit current levels. Hig...
Answer: A. common emitter
The common emitter configuration provides both high current gain and high voltage gain simultaneously. Multiplying these two substantial gains together yields the maximum overall power gain among all transistor setups. T...
Answer: B. less than 1
Alpha represents the ratio of collector current to emitter current in a bipolar junction transistor. Because a tiny fraction of emitter current escapes through the base, collector current is always smaller. Dividing a sm...
Answer: C. common emitter
The common emitter configuration combines high current gain with substantial output resistance to maximize voltage amplification. This optimal combination allows the circuit to multiply input voltage signals more effecti...
Answer: C. Ohm
Dimensional analysis of inductance divided by capacitance times resistance yields the fundamental unit of ohms. Inductance has dimensions of ohm-seconds while capacitance has dimensions of seconds per ohm. Simplifying th...
Answer: D. catenary
An overhead power conductor suspended freely between two support towers hangs under its own uniform dead weight. The mathematical curve formed by a flexible cable hanging under uniform gravitational loading is a catenary...
Answer: A. distributors
Feeders are heavy conductors designed to transport large amounts of electrical power without tapping loads. They link generating stations or major substations directly to local distribution networks and distributors. Thi...
Answer: B. Service mains
Service mains represent the final electrical conductors that physically link consumer premises to the local distribution grid. Utility companies install these dedicated lines to deliver electrical power directly to resid...
Answer: B. 2.7
Aluminum has a characteristic specific gravity value of approximately 2.7 relative to water. This density value makes aluminum significantly lighter than heavier structural metals like copper or steel. Specific gravity m...
