ETC ETC Electrical & Electronic Systems 2

Question 1

What instrument is used to measure electrical resistance in a circuit?

Accepted Answer

Ohmmeter

Answer

An ohmmeter measures electrical resistance in ohms and must be used on a de-energized circuit.

Question 2

In a three-phase power system, what is the phase angle between each phase?

Accepted Answer

120 degrees

Answer

In a balanced three-phase system, each of the three phases is separated by 120 electrical degrees.

Question 3

What does a power factor of 1.0 indicate about a circuit?

Accepted Answer

Current and voltage are perfectly in phase

Answer

A power factor of 1.0 means current and voltage are in phase, indicating a purely resistive load with no reactive power.

Question 4

Which type of circuit protection device automatically resets after a fault is cleared?

Accepted Answer

Circuit breaker

Answer

A circuit breaker can be reset after tripping, while a fuse must be replaced because its element melts during a fault.

Question 5

What is the function of a transformer in an electrical distribution system?

Accepted Answer

To change voltage levels between circuits

Answer

A transformer uses electromagnetic induction to step voltage up or down between two circuits without direct electrical connection.

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