Free FE Electrical and Computer Practice Questions

Sample Practice Questions

Try these 10 sample questions from the FE Electrical and Computer practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1A right triangle has legs of 8 m and 15 m. What is the length of its hypotenuse?

   1. A. 7 m
   2. B. 17 m
   3. C. 23 m
   4. D. 289 m

   Answer: B

   Explanation: The handbook states, "the square of the length of the hypotenuse equals the sum of the squares of the lengths of the other two sides." Therefore c = sqrt(8² + 15²) = sqrt(289) = 17 m.

   Reference: DOE Fundamentals Handbook: Mathematics, Volume 2 of 2 — Module 4, Pythagorean Theorem, page 1

2. 2Under NSPE Code section II.1.a, an engineer’s judgment is overruled in circumstances that endanger life or property. What notification is required?

   1. A. Notify the employer or client and other appropriate authority.
   2. B. Notify only the employer or client to preserve confidentiality.
   3. C. Notify the project insurer instead of the employer or client.
   4. D. Notify the employer or client only after an injury occurs.

   Answer: A

   Explanation: NSPE section II.1.a requires engineers to "notify their employer or client and such other authority as may be appropriate." The duty applies when the overruled judgment endangers life or property. Confidentiality does not erase this express ethical duty, and actual injury is not a prerequisite.

   Reference: NSPE Code of Ethics for Engineers — Rules of Practice, public-safety notification, paragraph a, PDF page 1

3. 3Which mobile carriers predominate in silicon made n-type by donor doping?

   1. A. Free electrons
   2. B. Holes
   3. C. Protons
   4. D. Positive donor ions

   Answer: A

   Explanation: Toshiba identifies the charge carriers as "free electrons". Donor doping supplies mobile electrons; positively ionized donors remain in the lattice and are not the mobile majority carriers.

   Reference: Toshiba: n-type Semiconductor — n-type Semiconductor, carrier explanation

4. 4At a circuit node, 5 A and 2 A enter, while 3 A and an unknown current leave. What is the unknown outgoing current?

   1. A. 2 A
   2. B. 4 A
   3. C. 7 A
   4. D. 10 A

   Answer: B

   Explanation: The handbook states, "The current arriving at any junction point in a circuit is equal to the current leaving that junction". Thus 5 + 2 = 3 + I, giving I = 4 A.

   Reference: DOE Fundamentals Handbook: Electrical Science, Volume 1 — Module 2, Kirchhoff’s Laws, page 42

5. 5A baseband signal contains no frequencies above 4 kHz. Which listed ideal sampling rate satisfies the strict Nyquist criterion for reconstructing any such signal?

   1. A. 4 kS/s
   2. B. 6 kS/s
   3. C. 8 kS/s
   4. D. 10 kS/s

   Answer: D

   Explanation: NI states that the sample rate must be "greater than twice" the highest frequency component. The strict condition is fs > 8 kS/s, so only 10 kS/s qualifies among these choices.

   Reference: NI: Acquiring an Analog Signal—Bandwidth, Nyquist Sampling Theorem, and Aliasing — Nyquist Sampling Theorem

6. 6A single-phase load draws 10 A RMS at 120 V RMS with power factor 0.8. What real power does it consume?

   1. A. 960 W
   2. B. 1,200 W
   3. C. 1,500 W
   4. D. 240 W

   Answer: A

   Explanation: The handbook gives "P = I2R = EI cosθ". With cosθ = 0.8, P = 120(10)(0.8) = 960 W.

   Reference: DOE Fundamentals Handbook: Electrical Science, Volume 3 — Module 9, True Power, equation 9-2, page 3

7. 7Two linear scalar blocks with transfer functions G₁(s) = 2/(s + 1) and G₂(s) = 3/(s + 2) are connected in cascade, with no intervening feedback. What is the overall transfer function?

   1. A. 5/[(s + 1)(s + 2)]
   2. B. 6/[(s + 1)(s + 2)]
   3. C. (5s + 7)/[(s + 1)(s + 2)]
   4. D. 6/(2s + 3)

   Answer: B

   Explanation: The series documentation gives "Generates a new system [sysn * ... *] sys2 * sys1." Cascaded scalar transfer functions multiply, yielding 6/[(s + 1)(s + 2)]. Adding numerators or denominators separately does not represent a cascade.

   Reference: Python Control Systems Library: series — control.series, description

8. 8An analog radio signal conveys its message by varying the amplitude of a sinusoidal carrier while keeping its carrier frequency fixed. Which modulation method is being used?

   1. A. Amplitude modulation
   2. B. Frequency modulation
   3. C. Phase modulation
   4. D. Pulse-code modulation

   Answer: A

   Explanation: NASA explains, "Either the amplitude or the frequency of the carrier wave can be varied, or modulated, in synchrony with the information-bearing signal. These methods are called amplitude modulation (AM) and frequency modulation (FM)." The stem varies carrier amplitude, so the method is AM. FM varies instantaneous frequency; phase modulation instead controls carrier phase, and PCM encodes samples as digital words.

   Reference: NASA Glenn: Learning About Earth From Space—Glossary S — Signal entry, modulation and frequency-division multiplexing

9. 9What is the decimal value of the unsigned binary number 101101₂?

   1. A. 41
   2. B. 43
   3. C. 45
   4. D. 53

   Answer: C

   Explanation: Arduino demonstrates binary positional weights using "1*2^4 + 1*2^3 + 0*2^2 + 1*2^1 + 0*2^0" for its example. Applying the same powers-of-two rule to 101101₂ gives 32 + 8 + 4 + 1 = 45. The other values result from missing or misplacing a set bit’s positional weight.

   Reference: Arduino Documentation: Bit Math with Arduino — The Binary System

10. 10For binary search on a sorted random-access array of n distinct keys, what is the tight asymptotic order of the worst-case number of key comparisons?

    1. A. Constant, Θ(1)
    2. B. Logarithmic, Θ(log n)
    3. C. Linear, Θ(n)
    4. D. Quadratic, Θ(n squared)

    Answer: B

    Explanation: NIST describes binary search as "repeatedly dividing the search interval in half" and states, "Run time is O(ln n)." Repeated halving requires a number of comparisons proportional to log n in the worst case. The logarithm’s base changes only a constant factor.

    Reference: NIST Dictionary of Algorithms and Data Structures: Binary Search — Definition and Note, runtime