FE Other Disciplines (NCEES Fundamentals of Engineering) — All Questions

The Code advises engineers to associate only with reputable persons and organizations mainly to:

• a.Avoid paying taxes
• b.Guarantee project profits
• c.Uphold the integrity and honor of the profession✓
• d.Increase billable hours

Engineers should conduct themselves honorably and associate with reputable parties to enhance the honor, reputation, and usefulness of the profession and protect public trust.

An action that is legal but still violates the engineering Code of Ethics should be:

• a.Ignored entirely
• b.Reported to the police
• c.Avoided, because ethical duties can exceed legal minimums✓
• d.Taken freely, since only the law matters

Professional ethics often demand more than the law requires. Legal compliance is a floor, not a ceiling; engineers must also honor the higher standards of their code.

If an engineer's professional judgment is overruled under circumstances endangering life or property, the engineer must:

• a.Accept it silently
• b.Immediately approve and stamp the overruled work anyway so the project stays on its schedule
• c.Destroy the project records
• d.Notify the employer or client and any appropriate authority of the possible consequences✓

The Code requires engineers whose judgment is overruled where safety is at stake to notify their employer or client and, as appropriate, other authorities of the potential consequences.

Modern engineering ethics increasingly asks engineers to weigh the societal and environmental impact of their work because:

• a.Impacts are never predictable
• b.Engineering decisions affect public welfare and future generations✓
• c.Only marketing teams handle impact
• d.Considering such societal factors is actually legally forbidden under most engineering statutes

Because engineering shapes infrastructure, safety, and the environment, the profession expects engineers to weigh sustainability and societal welfare as part of holding public welfare paramount.

An engineer under deadline pressure is tempted to report untested results as if verified. The ethical course is to:

• a.Report only verified data and disclose what remains untested✓
• b.Average guessed values
• c.Blame a subordinate later
• d.Report them as tested to meet the deadline

Objectivity and truthfulness require reporting only substantiated findings and clearly stating limitations. Fabricating or misrepresenting data violates the Code and endangers the public.

In a closed-loop control system, negative feedback is used primarily to:

• a.Reduce error by comparing output to the setpoint and correcting the difference✓
• b.Amplify measurement noise and progressively push the output further from its setpoint
• c.Increase steady-state error
• d.Convert the system to open-loop

Negative feedback subtracts a measurement of the output from the setpoint to form an error signal that drives the output toward the desired value, improving accuracy and stability.

In a PID controller, the derivative (D) term produces an output proportional to the:

• a.The running sum of all accumulated past error over time
• b.Constant setpoint value
• c.Square of the error
• d.Rate of change of the error✓

Derivative action responds to how fast the error is changing, adding anticipatory damping that reduces overshoot. Integral action instead addresses accumulated past error.

Which control action is chiefly responsible for eliminating steady-state (offset) error?

• a.Derivative
• b.Integral✓
• c.Proportional
• d.On-off (bang-bang)

The integral term accumulates error over time and keeps adjusting the output until the steady-state error is driven to zero, unlike pure proportional control, which leaves an offset.

A purely proportional controller applied to a process typically leaves:

• a.No error at all
• b.An unstable oscillation always
• c.A residual steady-state offset error✓
• d.Only derivative noise

Proportional-only control needs a nonzero error to produce the output that holds the process, so it settles with a residual offset. Adding integral action removes this offset.

A thermocouple generates a temperature-dependent voltage based on the:

• a.Piezoelectric effect
• b.Seebeck effect at a junction of two dissimilar metals✓
• c.A predictable change of electrical resistance with temperature
• d.Photoelectric effect

A thermocouple exploits the Seebeck effect: two dissimilar metals joined at a junction develop a voltage proportional to the temperature difference between the measuring and reference junctions.

A resistance temperature detector (RTD), such as a platinum Pt100, works because its:

• a.Voltage output rises through the thermoelectric Seebeck effect at a junction
• b.Capacitance drops with temperature
• c.Color changes with temperature
• d.Electrical resistance increases predictably with temperature✓

An RTD relies on the positive, nearly linear rise of metal resistance with temperature. Platinum RTDs are prized for stability and accuracy over wide ranges.

A common NTC thermistor differs from an RTD in that its resistance:

• a.Increases linearly with temperature
• b.Stays constant with temperature
• c.Depends only on pressure
• d.Decreases sharply and nonlinearly as temperature rises✓

A negative-temperature-coefficient (NTC) thermistor's resistance falls steeply and nonlinearly as temperature increases, giving high sensitivity over a narrow range.

A bonded metallic strain gauge measures strain by detecting the change in its:

• a.Electrical resistance as the foil stretches or compresses✓
• b.Magnetic polarity
• c.Mass
• d.Color

Stretching a strain gauge lengthens and thins its conductor, raising resistance, and vice versa. The gauge factor relates the fractional resistance change to strain.

A Wheatstone bridge is commonly used with a strain gauge to:

• a.Convert a small resistance change into a measurable voltage signal✓
• b.Generate a very high excitation voltage to drive the downstream amplifier stage
• c.Store electrical energy
• d.Rectify AC to DC

The bridge is balanced at zero strain; a small gauge-resistance change unbalances it, producing an output voltage proportional to strain that can then be amplified and read.

Industrial sensors often transmit a 4-20 mA current signal rather than a voltage mainly because current loops:

• a.Are considerably cheaper to generate than an equivalent voltage signal
• b.Eliminate the need for a power supply
• c.Cannot carry analog data
• d.Resist voltage drop over long wires and reveal a broken wire as 0 mA✓

A current signal is unaffected by wire resistance and voltage drop, so it stays accurate over long runs. The 4 mA live zero also lets 0 mA flag a broken loop or failed sensor.

A linear variable differential transformer (LVDT) is a sensor used to measure:

• a.Linear position or displacement✓
• b.Light intensity
• c.pH
• d.Temperature

An LVDT uses a movable magnetic core and paired secondary coils to produce a voltage proportional to the core's linear displacement, giving frictionless, high-resolution position sensing.

For a first-order measuring instrument, the time constant is the time to reach what percentage of a step change in the measured value?

• a.100%
• b.63.2%✓
• c.90%
• d.50%

After one time constant a first-order system reaches 63.2% (that is, 1 - e^-1) of its final value; about five time constants are needed to settle to roughly 99%.

A second-order system with a damping ratio (zeta) between 0 and 1 is:

• a.Underdamped, with an oscillatory response✓
• b.Overdamped
• c.Undamped
• d.Critically damped

For 0 < zeta < 1 the response overshoots and oscillates before settling (underdamped). zeta = 1 is critically damped (fastest without overshoot) and zeta > 1 is overdamped.

The key difference between a closed-loop and an open-loop control system is that the closed-loop system:

• a.Has no controller
• b.Ignores the measured output
• c.Uses feedback of the output to adjust its input✓
• d.Cannot correct for external disturbances acting on the process

A closed-loop (feedback) system measures its output and feeds it back to correct errors and reject disturbances; an open-loop system acts without checking the actual result.

The transfer function of a linear system is defined as the:

• a.Ratio of the Laplace transform of the output to that of the input, with zero initial conditions✓
• b.Time-domain product of the input and output signals evaluated at every instant without any transform
• c.Sum of all system poles
• d.Steady-state gain only

A transfer function G(s) = Y(s)/X(s) with zero initial conditions characterizes the system's dynamics in the s-domain, from which poles, zeros, and stability follow.

A unity-feedback loop has forward gain G = 10. What is the closed-loop gain, G/(1 + G)?

• a.11
• b.0.909✓
• c.10
• d.0.1

Closed-loop gain = G/(1 + GH) with H = 1 gives 10/(1 + 10) = 10/11 = 0.909. Feedback trades raw gain for accuracy, stability, and reduced sensitivity.

An instrument that consistently reads 5.00 g for a true 4.50 g mass, repeating within plus or minus 0.01 g, is best described as:

• a.Both accurate and precise
• b.Neither accurate nor precise
• c.Accurate but not precise
• d.Precise but not accurate✓

Precision is repeatability (the tight plus or minus 0.01 g spread) while accuracy is closeness to the true value (off by 0.50 g). The instrument is precise but inaccurate, a systematic bias error.

A continuous linear time-invariant system is stable if all poles of its transfer function lie:

• a.In the left half of the s-plane (negative real parts)✓
• b.In the right half of the s-plane, having positive real parts
• c.Exactly on the imaginary axis
• d.At the origin only

Stability requires every pole to have a negative real part (left-half s-plane), so transient terms e^(pt) decay. Any right-half-plane pole produces an unbounded, unstable response.