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Iowa Professional Engineer Examination
Advanced 100-Question Practice Exam
2026 | Questions & Answers with
Detailed Rationales | Complete Exam
Prep & Study Guide
1. A reinforced concrete beam is designed with tension-controlled behavior.
Which condition most directly provides the desired ductile response?
A. A large compression reinforcement ratio
B. A tension steel strain exceeding the specified tension-controlled limit
C. A concrete compressive strain below 0.001
D. A neutral axis located close to the tension face
Answer: A tension steel strain exceeding the specified tension-controlled limit
Rationale: A tension-controlled reinforced concrete section develops substantial
tensile strain before concrete compression failure, providing ductility and
warning before collapse.
, 2. A steel column has an effective length factor of 1.0 and an unbraced length
of 18 ft. If the radius of gyration about the governing axis is 2.25 in., what is
the approximate slenderness ratio?
A. 72
B. 84
C. 96
D. 108
Answer: 96
Rationale: KL/r = (18 × 12)/2.25 = 96. The governing slenderness ratio is based
on the least radius of gyration and effective length about the critical axis.
3. In geotechnical engineering, an increase in effective stress in a normally
consolidated clay deposit generally causes:
A. Expansion
B. Permanent compression
C. Immediate liquefaction
D. Reduction in total stress
Answer: Permanent compression
Rationale: Increasing effective stress beyond the previous maximum effective
stress causes virgin compression in normally consolidated clay, resulting in
permanent settlement.
4. A roadway has a design speed of 60 mph and a horizontal curve requiring
superelevation. Which factor is most directly balanced against
superelevation in determining the required curve radius?
A. Pavement thickness
B. Side friction
C. Drainage coefficient
D. Subgrade modulus
Answer: Side friction
,Rationale: Horizontal-curve design relates speed, radius, superelevation, and
allowable side friction. The available lateral resistance is shared between
pavement banking and tire-pavement friction.
5. A water treatment plant experiences a sudden increase in turbidity after
heavy rainfall. Which process is generally most effective for removing
suspended colloidal particles before filtration?
A. Chlorination
B. Coagulation and flocculation
C. Aeration
D. Softening
Answer: Coagulation and flocculation
Rationale: Coagulation destabilizes colloidal particles, while flocculation
promotes aggregation into larger particles that can be removed by
sedimentation and filtration.
6. In structural dynamics, resonance is most likely to occur when:
A. Damping is zero regardless of forcing frequency
B. Natural frequency is much greater than forcing frequency
C. Forcing frequency approaches a system natural frequency
D. Static load exceeds yield strength
Answer: Forcing frequency approaches a system natural frequency
Rationale: Dynamic amplification becomes significant when excitation
frequency approaches a natural frequency. Damping limits, but does not
eliminate, the resonant response.
7. A three-phase balanced load is supplied at 480 V line-to-line. If the line
current is 50 A and the power factor is 0.85, the approximate real power is:
A. 17.7 kW
B. 28.2 kW
, C. 35.3 kW
D. 42.4 kW
Answer: 35.3 kW
Rationale: P = √3 V I PF = 1.732(480)(50)(0.85) ≈ 35.3 kW.
8. For an ideal Rankine cycle, increasing boiler pressure while maintaining the
same turbine exit pressure generally:
A. Eliminates turbine work
B. Increases the average temperature of heat addition
C. Decreases thermal efficiency in all cases
D. Eliminates condenser operation
Answer: Increases the average temperature of heat addition
Rationale: Raising boiler pressure generally increases the average temperature
at which heat is supplied, which can improve Rankine-cycle efficiency when
other parameters are appropriately controlled.
9. A centrifugal pump operates at constant impeller diameter. If rotational
speed increases by 20%, the approximate change in ideal pump head is:
A. 20% increase
B. 40% increase
C. 44% increase
D. 73% increase
Answer: 44% increase
Rationale: Pump affinity laws give H₂/H₁ = (N₂/N₁)². Thus 1.2² = 1.44, or a 44%
increase in head.
10.A project specification requires concrete to achieve a target compressive
strength while maintaining low permeability. Which approach is generally
most effective?
Iowa Professional Engineer Examination
Advanced 100-Question Practice Exam
2026 | Questions & Answers with
Detailed Rationales | Complete Exam
Prep & Study Guide
1. A reinforced concrete beam is designed with tension-controlled behavior.
Which condition most directly provides the desired ductile response?
A. A large compression reinforcement ratio
B. A tension steel strain exceeding the specified tension-controlled limit
C. A concrete compressive strain below 0.001
D. A neutral axis located close to the tension face
Answer: A tension steel strain exceeding the specified tension-controlled limit
Rationale: A tension-controlled reinforced concrete section develops substantial
tensile strain before concrete compression failure, providing ductility and
warning before collapse.
, 2. A steel column has an effective length factor of 1.0 and an unbraced length
of 18 ft. If the radius of gyration about the governing axis is 2.25 in., what is
the approximate slenderness ratio?
A. 72
B. 84
C. 96
D. 108
Answer: 96
Rationale: KL/r = (18 × 12)/2.25 = 96. The governing slenderness ratio is based
on the least radius of gyration and effective length about the critical axis.
3. In geotechnical engineering, an increase in effective stress in a normally
consolidated clay deposit generally causes:
A. Expansion
B. Permanent compression
C. Immediate liquefaction
D. Reduction in total stress
Answer: Permanent compression
Rationale: Increasing effective stress beyond the previous maximum effective
stress causes virgin compression in normally consolidated clay, resulting in
permanent settlement.
4. A roadway has a design speed of 60 mph and a horizontal curve requiring
superelevation. Which factor is most directly balanced against
superelevation in determining the required curve radius?
A. Pavement thickness
B. Side friction
C. Drainage coefficient
D. Subgrade modulus
Answer: Side friction
,Rationale: Horizontal-curve design relates speed, radius, superelevation, and
allowable side friction. The available lateral resistance is shared between
pavement banking and tire-pavement friction.
5. A water treatment plant experiences a sudden increase in turbidity after
heavy rainfall. Which process is generally most effective for removing
suspended colloidal particles before filtration?
A. Chlorination
B. Coagulation and flocculation
C. Aeration
D. Softening
Answer: Coagulation and flocculation
Rationale: Coagulation destabilizes colloidal particles, while flocculation
promotes aggregation into larger particles that can be removed by
sedimentation and filtration.
6. In structural dynamics, resonance is most likely to occur when:
A. Damping is zero regardless of forcing frequency
B. Natural frequency is much greater than forcing frequency
C. Forcing frequency approaches a system natural frequency
D. Static load exceeds yield strength
Answer: Forcing frequency approaches a system natural frequency
Rationale: Dynamic amplification becomes significant when excitation
frequency approaches a natural frequency. Damping limits, but does not
eliminate, the resonant response.
7. A three-phase balanced load is supplied at 480 V line-to-line. If the line
current is 50 A and the power factor is 0.85, the approximate real power is:
A. 17.7 kW
B. 28.2 kW
, C. 35.3 kW
D. 42.4 kW
Answer: 35.3 kW
Rationale: P = √3 V I PF = 1.732(480)(50)(0.85) ≈ 35.3 kW.
8. For an ideal Rankine cycle, increasing boiler pressure while maintaining the
same turbine exit pressure generally:
A. Eliminates turbine work
B. Increases the average temperature of heat addition
C. Decreases thermal efficiency in all cases
D. Eliminates condenser operation
Answer: Increases the average temperature of heat addition
Rationale: Raising boiler pressure generally increases the average temperature
at which heat is supplied, which can improve Rankine-cycle efficiency when
other parameters are appropriately controlled.
9. A centrifugal pump operates at constant impeller diameter. If rotational
speed increases by 20%, the approximate change in ideal pump head is:
A. 20% increase
B. 40% increase
C. 44% increase
D. 73% increase
Answer: 44% increase
Rationale: Pump affinity laws give H₂/H₁ = (N₂/N₁)². Thus 1.2² = 1.44, or a 44%
increase in head.
10.A project specification requires concrete to achieve a target compressive
strength while maintaining low permeability. Which approach is generally
most effective?
