FE ELECTRICAL – FIRST SIMULATION

#1. [Digital Systems] In unsigned 4-bit arithmetic, adding 3 and 14 sets carry-out flag to:

1

depends on signed interpretation

undefined

0

#2. [Computer Networks] A router has routes 10.2.0.0/16, 10.2.32.0/19, and 10.2.32.128/25. Packet to 10.2.32.200 follows which route?

10.2.0.0/16

10.2.32.128/25 (longest-prefix match)

Default route only

10.2.32.0/19

#3. [Digital Systems] In unsigned 4-bit arithmetic, adding 0 and 6 sets carry-out flag to:

0

1

undefined

depends on signed interpretation

#4. [Communications] A TDM PCM system multiplexes 45 channels, each sampled at 16000 Hz with 12 bits/sample. Aggregate data rate is:

9.504 Mb/s

8.64 Mb/s

6.48 Mb/s

10.195 Mb/s

#5. [Probability and Statistics] A lot has independent defect probability 0.02 per board. For 10 boards, what is P(at least 2 defect)?

0.02

0.015

0.016

0.013

#6. [Control Systems] For unity-feedback type-0 system with open-loop DC gain K=8, unit-step steady-state error is:

0.139

0.091

0.1

0.111

#7. [Linear Systems] A transfer function has poles at s=-5.55 and s=-10.54. Dominant time constant is closest to:

0.18 s

0.198 s

0.162 s

0.148 s

#8. [Ethics and Professional Practice] You discover a grounding omission that violates code, but correcting it will delay commissioning and trigger penalties. What is the MOST ethical action?

Proceed temporarily and note it in final report

Document the hazard, notify responsible authority immediately, and halt affected work until corrected

Inform only your manager verbally and continue work

Let the contractor decide whether to disclose the issue

#9. [Engineering Economics] Compute capital recovery (EUAC) for P=$180,504, S=$49,397, n=6 years, i=10%.

41350.5 USD/yr

26282.1 USD/yr

35042.8 USD/yr

43803.5 USD/yr

#10. [Probability and Statistics] A communication node retransmits X times with PMF P(X=0,1,2,3) = {0.10, 0.35, 0.40, 0.15}. What is E[X]?

1.44

2

1.888

1.6

#11. [Computer Systems] Cache hit rate=0.96, hit time=2.22 ns, miss penalty=96.7 ns. AMAT is:

6.217 ns

4.663 ns

7.771 ns

7.336 ns

#12. [Electronics] Ideal inverting op-amp with Rin=14 kΩ, Rf=77 kΩ, Vin=0.513 V. Output is:

-2.312 V

-2.819 V

-3.101 V

-2.114 V

#13. [Mathematics] For f(t) = t^3 – t^2 + 5t, evaluate d f/dt at t = 5.

57.4

63

70

87.5

#14. [Mathematics] An engineer linearizes a calibration model and obtains equations 2x + 2y = 15 and x + 8y = 12. What is x?

6.56

6

8.8

8

#15. [Computer Networks] For IPv4 subnet /27, how many usable host addresses are available?

30

33

27

22.5

#16. [Engineering Economics] What present value is equivalent to a future replacement cost of $93,340 in 5 years at 11%?

45422.1 USD

55392.7 USD

41544.6 USD

49853.5 USD

#17. [Computer Systems] In interrupt-driven embedded systems, which design choice best reduces worst-case interrupt latency?

Move all ISR work into polling loops

Use deeply nested interrupts without masking policy

Keep critical sections short and prioritize ISRs with bounded execution

Disable caches during interrupt handling

#18. [Mathematics] In a fully connected sensor graph with 7 nodes, how many unique undirected links exist?

17.22

18.9

26.25

21

#19. [Properties of Electrical Materials] A conductor has resistivity 1.81e-08 Ω·m at 20°C and temperature coefficient 0.0040/°C. Estimate resistivity at 70°C.

2.18e-08 Ω·m

1.89e-08 Ω·m

1.59e-08 Ω·m

2.48e-08 Ω·m

#20. [Circuit Analysis] A branch dissipates 259 W with RMS current 4.62 A. Equivalent resistance is:

9.958 Ω

12.144 Ω

15.18 Ω

9.108 Ω

#21. [Circuit Analysis] An AC source of 144 Vrms drives impedance Z = 22 + j19 Ω. RMS current magnitude is:

5.845 A

6.192 A

4.954 A

5.449 A

#22. [Power Systems] Transformer no-load secondary voltage is 122 V and full-load is 118 V. Voltage regulation is:

2.542 %

3.729 %

4.237 %

3.39 %

#23. [Electromagnetics] Transmission line has Z0=61 Ω and load ZL=76 Ω (real). Reflection coefficient Γ at load is:

0.109

0.129

0.099

0.12

#24. [Circuit Analysis] In an RL step response with V=12 V, R=43 Ω, L=0.470 H, find i(t) at t=0.038 s.

0.222 A

0.271 A

0.338 A

0.298 A

#25. [Power Systems] A balanced 3-phase load consumes 130 kW at 397 V line-line and pf=0.80 lagging. Line current is:

259.6 A

294.9 A

236.0 A

212.4 A

#26. [Properties of Electrical Materials] A parallel-plate capacitor originally has air dielectric and unchanged geometry. If replaced by a dielectric with relative permittivity εr, capacitance changes by what factor?

0.147

46.24

2.608

6.8

#27. [Communications] For an AM wave, envelope Vmax=9.33 and Vmin=2.09. Modulation index m is:

0.634

0.52

0.698

0.476

#28. [Mathematics] Compute the integral ∫_0^4 x^2 dx.

19.2

21.333

16

23.467

#29. [Engineering Economics] For a test fixture: fixed cost $148,325, unit price $100, variable cost $38. Break-even quantity is closest to:

2153.1 units

1794.3 units

2392.3 units

1961.7 units

#30. [Circuit Analysis] Node A is connected to 34 V through 2 Ω and to 6 V through 3 Ω. What is node voltage Va (no load)?

17.1 V

26.904 V

28.5 V

22.8 V

#31. [Computer Networks] Which security control BEST addresses lateral movement after initial endpoint compromise?

Network segmentation with least-privilege access and east-west monitoring

Using only perimeter firewalls without internal controls

Disabling all ICMP traffic globally

Increasing WAN bandwidth

#32. [Mathematics] A phasor is V = 4 + j5. What is |V|?

7.043

6.403

4.802

5.763

#33. [Software Engineering] Which data structure gives O(1) average-time lookup for symbol tables while allowing occasional rehash operations?

Singly linked list

Unbalanced binary search tree

Hash table

Binary heap

#34. [Probability and Statistics] Assuming normal process variation with mean 114 and std dev 15, what is the 95th percentile?

173.3

124.8

163.6

138.7

#35. [Signal Processing] A tone at 7100 Hz is sampled at fs=8000 Hz. Observed baseband alias frequency is:

900 Hz

738 Hz

1062 Hz

1125 Hz

#36. [Software Engineering] A loop nest runs: for i=1..n, for j=1..i. Time complexity is:

O(n)

O(n^2)

O(n^3)

O(log n)

#37. [Signal Processing] For y[n]=0.54y[n-1]+(0.15)y[n-2]+x[n], which is correct?

Always stable because coefficients are finite

Always unstable for second-order IIR filters

BIBO stable (dominant poles inside unit circle)

Cannot determine stability without x[n]

#38. [Electronics] Ideal inverting op-amp with Rin=17 kΩ, Rf=47 kΩ, Vin=0.763 V. Output is:

-1.729 V

-1.582 V

-2.488 V

-2.109 V

#39. [Mathematics] An engineer linearizes a calibration model and obtains equations 3x + 2y = 11 and x + 6y = 5. What is x?

3.562

2.672

3.919

3.206

#40. [Circuit Analysis] A current source 3 A feeds two parallel resistors 5 Ω and 12 Ω. Node voltage across the pair is:

12.494 V

10.588 V

9.529 V

13.235 V

#41. [Circuit Analysis] A Thevenin source Vth=27 V with Rth=7 Ω feeds RL=15 Ω. Load current is:

1.448 A

1.534 A

1.227 A

0.92 A

#42. [Signal Processing] For an ideal 10-bit ADC, quantization-limited SQNR is closest to:

55.764 dB

73.113 dB

50.807 dB

61.96 dB

#43. [Ethics and Professional Practice] During RF testing, PPE requirements are being ignored in a high-field area. Your best professional response is to:

Stop testing and enforce safety controls before resuming

Record violations and address them at project closeout

Move only your own team out of the area

Continue if measured exposure is usually below limits

#44. [Linear Systems] For G(s)=1/(s+7), unit-step response final value is:

0.156

0.125

0.138

0.102

#45. [Digital Systems] Which statement about asynchronous inputs to flip-flops is most accurate?

They are safe if setup time is met at the source

They never affect MTBF in digital systems

They can induce metastability and require synchronization before use in synchronous logic

They eliminate race conditions by definition

#46. [Computer Systems] Compared with programmed I/O, DMA primarily improves system performance by:

Making memory accesses deterministic under all loads

Increasing ALU clock frequency directly

Eliminating the need for interrupts

Transferring bulk data with minimal CPU intervention

#47. [Digital Systems] Minimum number of flip-flops required for a MOD-9 synchronous counter is:

4

3.6

5

3.28

#48. [Circuit Analysis] A Thevenin source Vth=33 V with Rth=12 Ω feeds RL=16 Ω. Load current is:

0.884 A

1.179 A

1.061 A

1.473 A

#49. [Electromagnetics] For a lossless medium with εr=4.0 and μr=1, intrinsic impedance η is:

154.6 Ω

141.4 Ω

188.5 Ω

207.4 Ω

#50. [Engineering Economics] A retrofit costs $188,366 now and saves $37,576/year for 6 years. At MARR = 12%, what is NPV?

-25406.8 USD

-42344.7 USD

-27778.1 USD

-33875.8 USD

#51. [Computer Systems] Cache hit rate=0.97, hit time=2.31 ns, miss penalty=51.0 ns. AMAT is:

4.009 ns

3.006 ns

3.287 ns

4.73 ns

#52. [Electronics] Using square-law saturation model Id=0.5k(VGS−VT)^2, find Id for k=0.0014 A/V², VGS=3.36 V, VT=1.43 V.

2.977 mA

2.523 mA

3.154 mA

2.069 mA

#53. [Digital Systems] Which expression is equivalent to Boolean function F = A’B + AB (sum of products)?

A

A’ + B’

B

A + B

#54. [Control Systems] Increasing integral gain Ki in a PID controller most directly tends to:

Eliminate need for derivative action in all plants

Reduce sensor noise sensitivity at high frequency

Increase phase margin and always improve damping

Reduce steady-state error while risking increased overshoot/oscillation

#55. [Mathematics] For f(t) = t^3 – t^2 + 5t, evaluate d f/dt at t = 4.

45

36.9

33.75

56.25

#56. [Mathematics] A phasor is V = 7 + j7. What is |V|?

10.889

9.899

8.118

7.425

#57. [Electronics] In instrumentation design, which action most effectively reduces common-mode interference in low-level sensor measurements?

Place the sensor farther from the instrumentation amplifier

Increase ADC sampling rate without changing front-end topology

Use differential signaling with high CMRR front-end and proper shield grounding

Use single-ended wiring and average more samples

#58. [Circuit Analysis] An AC source of 161 Vrms drives impedance Z = 14 + j16 Ω. RMS current magnitude is:

8.936 A

6.816 A

5.68 A

7.573 A

#59. [Power Systems] Ideal transformer with turns ratio Np:Ns=4:1 feeds load 27 Ω on secondary. Reflected primary impedance is:

1.688 Ω

1.991 Ω

2.109 Ω

1.519 Ω

#60. [Mathematics] Compute the integral ∫_0^5 x^2 dx.

49.167

41.667

37.5

52.083

#61. [Computer Systems] A 32-bit, direct-mapped cache has 256 sets and 32-byte blocks. Tag bits per line are:

15.58

17.1

19

23.75

#62. [Electromagnetics] For a long straight conductor carrying 73 A, magnetic flux density at radius 0.081 m is:

1.98e-04 T

1.35e-04 T

2.12e-04 T

1.80e-04 T

#63. [Electronics] Half-wave rectifier with peak input 23 V, diode drop 0.7 V, RL=671 Ω. Approximate average load current:

10.579 mA

7.934 mA

8.675 mA

13.223 mA

#64. [Mathematics] In a fully connected sensor graph with 9 nodes, how many unique undirected links exist?

27

36

29.52

32.4

#65. [Linear Systems] For a 2nd-order system with damping ratio ζ=0.73 and ωn=13.93 rad/s, estimate 2% settling time.

0.489 s

0.43 s

0.391 s

0.321 s

#66. [Circuit Analysis] Node A is connected to 25 V through 4 Ω and to 17 V through 6 Ω. What is node voltage Va (no load)?

23.98 V

25.724 V

19.62 V

21.8 V

#67. [Circuit Analysis] A current source 10 A feeds two parallel resistors 7 Ω and 12 Ω. Node voltage across the pair is:

44.211 V

48.632 V

33.158 V

39.789 V

#68. [Communications] For an AM wave, envelope Vmax=8.53 and Vmin=1.51. Modulation index m is:

0.875

0.7

0.77

0.63

#69. [Control Systems] A standard 2nd-order closed-loop system has damping ratio ζ=0.74. Percent overshoot is closest to:

2.465 %

2.958 %

3.287 %

3.616 %

#70. [Software Engineering] Worst-case comparisons for binary search on sorted array of size 256 are closest to:

10

9.44

6.56

8

#71. [Digital Systems] Pipeline stage has tCQ=0.98 ns, combinational delay=5.54 ns, setup=1.04 ns. Max clock frequency is:

132.5 MHz

108.6 MHz

156.3 MHz

145.7 MHz

#72. [Communications] Using Shannon capacity C = B log2(1+SNR), with B=2.0 MHz and linear SNR=20, capacity is:

9.663 Mb/s

8.785 Mb/s

7.906 Mb/s

10.366 Mb/s

#73. [Ethics and Professional Practice] A former employer’s proprietary control code could shorten your current project by weeks. What is the proper action?

Use it temporarily and remove before delivery

Reuse only non-commented sections

Do not reuse protected code; obtain permission or develop an original implementation

Reuse code if variable names are changed

#74. [Computer Networks] Ignoring loss, TCP throughput with receive window 256 kB and RTT 40 ms is approximately:

47.186 Mb/s

57.672 Mb/s

61.866 Mb/s

52.429 Mb/s

#75. [Ethics and Professional Practice] A client asks you to stamp a design prepared entirely by another engineer that you did not supervise. What should you do?

Decline to seal until you have sufficient responsible charge and verification

Seal it if the schedule is critical

Seal it if the other engineer signs an email attestation

Seal only the pages that look correct on quick review

#76. [Digital Systems] A static-1 hazard in combinational logic is typically mitigated by:

Replacing all AND gates with XOR gates

Adding consensus terms to cover adjacent minterms

Reducing supply voltage to slow transitions

Clocking the combinational block

#77. [Power Systems] Transformer no-load secondary voltage is 128 V and full-load is 111 V. Voltage regulation is:

13.784 %

12.559 %

15.315 %

18.072 %

#78. [Digital Systems] Pipeline stage has tCQ=1.87 ns, combinational delay=4.54 ns, setup=1.07 ns. Max clock frequency is:

100.3 MHz

167.2 MHz

120.4 MHz

133.8 MHz

#79. [Computer Systems] By Amdahl’s law, fraction parallelizable p=0.58 with accelerator speedup 2.73. Overall speedup is:

1.586

1.871

1.744

1.427

#80. [Probability and Statistics] 25% of failures are due to power-stage faults. A thermal alarm appears with conditional probabilities P(A|power) and P(A|non-power) as given. What is P(power | alarm)?

0.512

0.625

0.737

0.781

#81. [Software Engineering] Which testing strategy is best for validating boundary behavior of ADC register parsing logic?

Integration testing only after deployment

Random testing only, without deterministic edge cases

Boundary value analysis with explicit min/max and off-by-one cases

Code formatting checks as primary validation

#82. [Properties of Electrical Materials] Estimate skin depth δ for a conductor with σ=4.11e+07 S/m, μr=100, at f=60 Hz.

7.60e-04 m

9.12e-04 m

8.31e-04 m

0.001 m

#83. [Circuit Analysis] Node A is connected to 28 V through 6 Ω and to 17 V through 5 Ω. What is node voltage Va (no load)?

22 V

19.8 V

16.5 V

25.96 V

#84. [Linear Systems] For system y” + 3y’ + 2y = u(t), which statement about stability is true?

Marginally stable because second-order systems always oscillate

Stable because all coefficients are positive and roots have negative real parts

Unstable because input is a step function

Unstable unless b > a^2

#85. [Mathematics] For first-order decay dy/dt = -2y with y(0)=1, find y(0.87 s).

0.209

0.133

0.177

0.16

#86. [Digital Systems] Minimum number of flip-flops required for a MOD-7 synchronous counter is:

3.54

3.3

3.75

3

#87. [Properties of Electrical Materials] A package heat spreader has k=139.3 W/m·K, area=3.59e-04 m², thickness=0.027 m, and ΔT=47 K. Conduction heat rate is:

87.701 W

78.931 W

65.776 W

103.5 W

#88. [Power Systems] At a 11 kV bus with Thevenin reactance 0.169 Ω (line-line basis), 3-phase bolted fault current is approximately:

28241.2 A

37655.0 A

41420.5 A

44432.9 A

#89. [Engineering Economics] Two design alternatives have scenario payoffs (high/medium/low demand): A=[140k,60k,-20k], B=[90k,70k,10k] with probabilities [0.2,0.5,0.3]. Best EMV is:

66080 USD

50400 USD

56000 USD

45920 USD

#90. [Circuit Analysis] A branch dissipates 500 W with RMS current 5.05 A. Equivalent resistance is:

24.511 Ω

14.707 Ω

16.079 Ω

19.609 Ω

#91. [Power Systems] A balanced 3-phase load consumes 146 kW at 215 V line-line and pf=0.84 lagging. Line current is:

466.7 A

350.0 A

382.7 A

583.3 A

#92. [Circuit Analysis] In an RL step response with V=21 V, R=25 Ω, L=0.334 H, find i(t) at t=0.030 s.

0.562 A

0.75 A

0.825 A

0.884 A

#93. [Electronics] A BJT in active mode has β=113 and base current 80.1 µA. Collector current is closest to:

10.682 mA

8.147 mA

9.052 mA

11.315 mA

#94. [Signal Processing] A first-order analog low-pass has cutoff 800 Hz. At cutoff frequency, output magnitude relative to passband is:

0 dB (unity)

-6 dB (half amplitude)

+3 dB (resonant peak)

-3 dB (approximately 0.707 of passband amplitude)

#95. [Mathematics] For first-order decay dy/dt = -6y with y(0)=1, find y(1.40 s).

2.29e-04

2.70e-04

1.88e-04

2.06e-04

#96. [Electronics] A BJT in active mode has β=85 and base current 42.5 µA. Collector current is closest to:

4.513 mA

3.61 mA

2.96 mA

3.249 mA

#97. [Control Systems] For unity-feedback type-0 system with open-loop DC gain K=2, unit-step steady-state error is:

0.393

0.273

0.333

0.367

#98. [Control Systems] For characteristic equation s^2 + 4s + 8=0, which range of k ensures stability?

k > 16 only

k = 0 only

k < 0

k > 0

#99. [Power Systems] Ideal transformer with turns ratio Np:Ns=5:1 feeds load 23 Ω on secondary. Reflected primary impedance is:

0.92 Ω

0.754 Ω

1.086 Ω

0.828 Ω

#100. [Signal Processing] For FIR filter y[n]=x[n]+0.5x[n-1]+0.25x[n-2], with x[0]=5, x[1]=1, x[2]=1, find y[2].

2.062

2.75

2.255

3.025

#101. [Communications] Compared with pure FDM, which is a key advantage of CDMA in multipath-rich mobile channels?

It guarantees zero near-far effects without power control

It requires fewer chips than symbols for spread-spectrum operation

Processing gain enables interference averaging and supports soft capacity

It eliminates the need for synchronization entirely

#102. [Power Systems] A component has reactance 0.191 pu on 100 MVA base (same kV base). On 25 MVA base, pu reactance is:

0.043 pu

0.053 pu

0.06 pu

0.048 pu

#103. [Power Systems] A 4-pole induction motor on 60 Hz runs at 1793 rpm. Rotor current frequency is closest to:

0.233 Hz

0.257 Hz

0.175 Hz

0.191 Hz

#104. [Mathematics] An engineer linearizes a calibration model and obtains equations 4x + 2y = 16 and x + 8y = 4. What is x?

3.66

4.067

3.335

4.473

#105. [Electromagnetics] If electric field changes at dE/dt=2.56e+06 V/m·s in a dielectric with permittivity 3.54e-11 F/m, displacement current density Jd is:

7.43e-05 A/m²

6.80e-05 A/m²

9.07e-05 A/m²

9.97e-05 A/m²

#106. [Communications] For M-ary signaling with M=2 and bit rate 1000 kb/s, symbol rate is:

820 ksym/s

1100 ksym/s

1180 ksym/s

1000 ksym/s

#107. [Electronics] An ideal 10-bit ADC with Vref=3.3 V measures Vin=1.380 V. Output code is closest to:

427

350.1

469.7

384.3

#108. [Control Systems] A loop has crossover ωc=22.9 rad/s and phase margin 43.7°. Which interpretation is best?

System is unstable because crossover frequency is finite

Positive phase margin indicates closed-loop stability with moderate robustness

Phase margin does not relate to time-domain overshoot

System is marginally stable only if gain margin is exactly 0 dB

#109. [Control Systems] A standard 2nd-order closed-loop system has damping ratio ζ=0.77. Percent overshoot is closest to:

1.681 %

2.645 %

2.242 %

1.838 %

#110. [Linear Systems] For low-pass H(jω)=1/(1+jωτ) with τ=0.387 s, find |H(jω)| at ω=12 rad/s.

0.189

0.248

0.173

0.21

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