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Question 1Engineering Fundamentals and Applied Science

In a steady-state heat conduction problem through a plane wall, the temperature profile is linear. What does this imply about the thermal conductivity of the wall material?

  1. It decreases linearly with temperature.
  2. It is proportional to the heat flux squared.
  3. It increases linearly with temperature.
  4. It is constant with temperature. Correct answer.

Explanation

Fourier's law states that heat flux equals negative thermal conductivity times the temperature gradient. A linear temperature profile means the gradient is constant throughout the wall, so under steady one-dimensional flow the conductivity must also be constant. If conductivity varied with temperature, the profile would curve rather than remain straight.

Question 2Engineering Fundamentals and Applied Science

A simply supported beam carries a concentrated load at midspan. Where does the maximum bending moment occur?

  1. At the supports
  2. At the quarter points
  3. At midspan under the load Correct answer.
  4. Uniformly along the beam

Explanation

For a simply supported beam with a central point load, the bending moment diagram is a triangle peaking directly beneath the load. Reactions are equal at each support, and the moment grows linearly from zero at the supports to a maximum at midspan. The value is load times span divided by four.

Question 3Engineering Fundamentals and Applied Science

Which dimensionless group expresses the ratio of inertial forces to viscous forces in fluid flow?

  1. Froude number
  2. Prandtl number
  3. Mach number
  4. Reynolds number Correct answer.

Explanation

The Reynolds number is defined as density times velocity times characteristic length divided by dynamic viscosity. It quantifies the relative importance of inertial versus viscous effects and determines whether flow is laminar or turbulent. The other groups compare different force balances.

Question 4Engineering Fundamentals and Applied Science

In a thermodynamic cycle operating between two thermal reservoirs, what does the second law of thermodynamics forbid?

  1. A device that produces work while rejecting some heat
  2. A refrigerator requiring work input
  3. A reversible cycle with efficiency below the Carnot value
  4. A device whose thermal efficiency equals one Correct answer.

Explanation

The Kelvin-Planck statement of the second law says no cyclic device can convert all absorbed heat into work. A thermal efficiency of one would require rejecting zero heat to the cold reservoir, which is impossible for a cyclic engine. Real engines must reject some heat, capping efficiency below unity.

Question 5Engineering Fundamentals and Applied Science

A resistor of 220 ohms carries a current of 0.5 A. What power is dissipated in the resistor?

  1. 27.5 W
  2. 110 W
  3. 440 W
  4. 55 W Correct answer.

Explanation

Joule heating power equals current squared times resistance. Squaring 0.5 A gives 0.25 A squared, and multiplying by 220 ohms yields 55 W. Alternatively, voltage is 110 V and power equals voltage times current, again giving 55 W.

Question 6Engineering Fundamentals and Applied Science

Which statement correctly describes the role of a control rod in a nuclear fission reactor?

  1. It provides the initial neutrons that start the reaction.
  2. It reflects escaping neutrons back into the core.
  3. It moderates neutron speed to sustain the chain reaction.
  4. It absorbs neutrons to reduce the multiplication factor. Correct answer.

Explanation

Control rods are made of strong neutron absorbers such as boron or cadmium. Inserting them removes neutrons from the population, lowering the effective multiplication factor and reducing reactor power. Their purpose is regulation and shutdown, not moderation or reflection.

Question 7Engineering Fundamentals and Applied Science

A material has a face-centered cubic crystal structure. How many atoms are effectively contained within one unit cell?

  1. 4 Correct answer.
  2. 1
  3. 8
  4. 2

Explanation

In an FCC cell there are eight corner atoms each shared by eight cells, contributing one atom, plus six face atoms each shared by two cells, contributing three atoms. The total is four atoms per unit cell. This count distinguishes FCC from BCC and simple cubic structures.

Question 8Engineering Fundamentals and Applied Science

Which of the following best defines the stress intensity factor in linear elastic fracture mechanics?

  1. A parameter quantifying the stress field near a crack tip for a given load and geometry Correct answer.
  2. The average stress on the uncracked cross section
  3. The maximum stress a material can endure before yielding
  4. The strain energy stored per unit volume of the material

Explanation

The stress intensity factor, denoted K, characterizes the magnitude of the crack-tip stress field. It depends on applied stress, crack size, and a geometry factor, and is compared with the fracture toughness to assess crack growth. It is not a simple average stress or an energy density.

Question 9Engineering Fundamentals and Applied Science

Water flows through a pipe that narrows from a 0.10 m diameter section to a 0.05 m diameter section. If the velocity in the larger section is 2 m/s, what is the velocity in the smaller section, assuming incompressible flow?

  1. 6 m/s
  2. 16 m/s
  3. 8 m/s Correct answer.
  4. 4 m/s

Explanation

Continuity for incompressible flow requires the product of area and velocity to be constant. The area ratio equals the square of the diameter ratio, so halving the diameter reduces area by a factor of four. The velocity therefore rises by the same factor, from 2 m/s to 8 m/s.

Question 10Engineering Fundamentals and Applied Science

A steel bar 2 m long with a coefficient of thermal expansion of 12e-6 per degree Celsius is heated uniformly by 50 degrees C while both ends are free. What is the change in length?

  1. 2.4 mm
  2. 12 mm
  3. 1.2 mm Correct answer.
  4. 0.6 mm

Explanation

Free thermal expansion equals the product of the coefficient, original length, and temperature change. Multiplying 12e-6 by 2 m by 50 K gives 1.2e-3 m, or 1.2 mm. Because the ends are free, no thermal stress develops.

Question 11Engineering Fundamentals and Applied Science

In a vapor-compression refrigeration cycle, what is the function of the expansion valve?

  1. It throttles the refrigerant from condensing to evaporating pressure. Correct answer.
  2. It transfers heat from the refrigerant to the surroundings.
  3. It superheats the vapor before it enters the compressor.
  4. It compresses the refrigerant vapor to the condensing pressure.

Explanation

The expansion valve throttles high-pressure liquid refrigerant down to the evaporator pressure, causing a temperature drop and partial flashing. This low-temperature mixture then absorbs heat in the evaporator. Compression and heat rejection occur in other components.

Question 12Engineering Fundamentals and Applied Science

A three-phase induction motor has 4 poles and is supplied at 60 Hz. What is the synchronous speed?

  1. 900 rpm
  2. 1200 rpm
  3. 1800 rpm Correct answer.
  4. 3600 rpm

Explanation

Synchronous speed equals 120 times frequency divided by the number of poles. With 60 Hz and 4 poles, that gives 7200 divided by 4, or 1800 rpm. Rotor speed is slightly lower because of slip.

Question 13Engineering Fundamentals and Applied Science

In a closed-loop control system, what does a proportional-integral controller primarily add compared with proportional-only control?

  1. Reduction of the system order
  2. Elimination of steady-state error Correct answer.
  3. Guaranteed stability for all gains
  4. Instantaneous response to setpoint changes

Explanation

The integral term accumulates past error, allowing the controller to drive steady-state error to zero for a step input. Proportional-only control typically leaves a residual offset. The integral action improves accuracy but can reduce stability margins.

Question 14Engineering Fundamentals and Applied Science

A tensile test specimen with an original gauge length of 50 mm fractures at a gauge length of 60 mm. What is the percent elongation?

  1. 16.7 percent
  2. 120 percent
  3. 10 percent
  4. 20 percent Correct answer.

Explanation

Percent elongation equals the change in length divided by the original length, multiplied by 100. The change is 10 mm over an original 50 mm, giving 0.20 or 20 percent. This is a standard ductility measure in tensile testing.

Question 15Engineering Fundamentals and Applied Science

Which phenomenon describes the loss of stiffness and strength in a polymer as it absorbs moisture or is exposed to elevated temperature over time?

  1. Work hardening
  2. Creep
  3. Plasticization Correct answer.
  4. Fatigue

Explanation

Plasticization occurs when small molecules such as water or certain additives enter the polymer and increase chain mobility. This lowers the glass transition temperature and reduces stiffness and strength. Creep and fatigue are time- or cycle-dependent mechanical responses, not diffusion-driven softening.

Question 16Engineering Fundamentals and Applied Science

An ideal Otto cycle has a compression ratio of 8 and the working fluid has a specific heat ratio of 1.4. What is the thermal efficiency?

  1. 0.56 Correct answer.
  2. 0.43
  3. 0.68
  4. 0.80

Explanation

Otto cycle efficiency equals one minus the compression ratio raised to the power one minus the specific heat ratio. With a ratio of 8 and gamma of 1.4, the term 8 raised to the negative 0.4 is about 0.435, so efficiency is roughly 0.565. This is the air-standard idealization.

Question 17Engineering Fundamentals and Applied Science

In a hydroelectric plant, water falls 100 m and flows at 10 cubic meters per second. Taking water density as 1000 kg per cubic meter and gravitational acceleration as 9.81 m/s squared, what is the ideal power available?

  1. 0.98 MW
  2. 98.1 MW
  3. 981 MW
  4. 9.81 MW Correct answer.

Explanation

Hydraulic power equals density times gravitational acceleration times volumetric flow rate times head. Multiplying 1000, 9.81, 10, and 100 gives about 9.81 million watts, or 9.81 MW. Actual output is lower because of turbine and generator losses.

Question 18Engineering Fundamentals and Applied Science

Which quantity is conserved across a normal shock wave in a steady one-dimensional compressible flow?

  1. Entropy
  2. Stagnation pressure
  3. Static temperature
  4. Mass flow rate per unit area Correct answer.

Explanation

The continuity equation requires that mass flux, density times velocity, remain constant across a normal shock. Entropy increases and stagnation pressure falls because the shock is irreversible. Static temperature rises through the shock as kinetic energy converts to internal energy.

Question 19Engineering Fundamentals and Applied Science

A structural member is loaded such that the principal stresses are 100 MPa and 40 MPa. What is the maximum shear stress in the plane of these stresses?

  1. 20 MPa
  2. 30 MPa Correct answer.
  3. 70 MPa
  4. 140 MPa

Explanation

In-plane maximum shear stress equals half the difference between the two principal stresses. Subtracting 40 from 100 gives 60 MPa, and halving yields 30 MPa. This is the radius of Mohr's circle for the in-plane state.

Question 20Engineering Fundamentals and Applied Science

Which mechanism dominates heat transfer from a hot horizontal plate facing upward to still air?

  1. Natural convection Correct answer.
  2. Conduction through the air layer
  3. Radiation only
  4. Forced convection

Explanation

An upward-facing hot plate in still air creates buoyancy-driven circulation because heated air near the surface rises. Natural convection therefore dominates the convective transport, often combined with radiation. Conduction is limited to a thin boundary layer and forced convection requires external flow.

Question 21Engineering Fundamentals and Applied Science

A flywheel with a moment of inertia of 5 kg m squared accelerates uniformly from rest to 20 rad/s in 4 s. What average torque is required?

  1. 5 N m
  2. 20 N m
  3. 100 N m
  4. 25 N m Correct answer.

Explanation

Angular acceleration equals the change in angular velocity divided by time, giving 20 divided by 4, or 5 rad/s squared. Torque equals moment of inertia times angular acceleration, so 5 times 5 yields 25 N m. This follows Newton's second law for rotation.

Question 22Engineering Fundamentals and Applied Science

A simply supported beam of length L carries a uniformly distributed load w per unit length over its entire span. Where does the maximum bending moment occur and what is its magnitude?

  1. At midspan, magnitude wL squared over 8 Correct answer.
  2. At midspan, magnitude wL squared over 4
  3. At the supports, magnitude wL squared over 8
  4. At quarter span, magnitude wL squared over 12

Explanation

For a uniformly loaded simply supported beam, the reactions are each wL over 2 and the moment diagram is parabolic. The peak occurs at midspan with magnitude w times L squared divided by 8. The moment is zero at the simple supports.

Question 23Engineering Fundamentals and Applied Science

In a binary eutectic phase diagram, what distinguishes the eutectic composition from all other compositions at the eutectic temperature?

  1. It is the composition with the highest melting point in the system.
  2. It is the composition at which liquid transforms directly into two solid phases simultaneously. Correct answer.
  3. It is the composition at which a single solid phase is stable over the widest range.
  4. It is the only composition that remains fully liquid at that temperature.

Explanation

At the eutectic point the liquid is in equilibrium with two solid phases and solidifies isothermally into both of them. This reaction occurs at the lowest melting temperature for the system, not the highest. Other compositions freeze over a temperature range instead.

Question 24Engineering Fundamentals and Applied Science

A feedback system has an open-loop transfer function with a gain that increases until the phase margin reaches zero. What does this condition indicate?

  1. The system is marginally stable at that gain, defining the gain margin. Correct answer.
  2. The steady-state error is zero.
  3. The damping ratio equals one.
  4. The system has infinite gain margin.

Explanation

When the loop gain is raised until the phase crossover occurs at unity magnitude, the closed-loop system reaches the stability boundary. The gain margin is the factor by which gain can be increased before this happens. A zero phase margin alone signals marginal stability at the current gain, and the gain margin quantifies the distance to that point.

Question 25Engineering Fundamentals and Applied Science

A Brayton cycle with regeneration is used for power generation. Under what condition does regeneration improve thermal efficiency most?

  1. When the pressure ratio equals one
  2. When the working fluid is an ideal gas with constant specific heats
  3. When the compressor pressure ratio is very high
  4. When the turbine exhaust temperature exceeds the compressor exit temperature Correct answer.

Explanation

Regeneration recovers heat from the turbine exhaust to preheat the air leaving the compressor. It is effective only when the exhaust is hotter than the compressed air, which occurs at lower pressure ratios. At high pressure ratios the compressor exit temperature approaches or exceeds the exhaust temperature, so regeneration provides little benefit.

Question 26Engineering Fundamentals and Applied Science

A cylindrical pressure vessel with an internal diameter of 1.0 m and a wall thickness of 10 mm carries an internal pressure of 2 MPa. What is the hoop (circumferential) stress in the wall, treating it as a thin-walled vessel?

  1. 50 MPa
  2. 200 MPa
  3. 100 MPa Correct answer.
  4. 25 MPa

Explanation

For a thin-walled cylinder the hoop stress is σ = pD/(2t), where D is the internal diameter and t the wall thickness. Substituting gives 2 MPa × 1000 mm / (2 × 10 mm) = 100 MPa. The longitudinal stress would be half this value, 50 MPa, but the question asks for the circumferential direction.

Question 27Engineering Fundamentals and Applied Science

In a solid circular shaft of diameter d transmitting a torque T, which expression gives the maximum torsional shear stress?

  1. 8T/(πd³)
  2. 16T/(πd³) Correct answer.
  3. 32T/(πd³)
  4. T/(πd³)

Explanation

Torsional shear stress is τ = Tr/J, and the polar second moment of area for a solid circle is J = πd⁴/32. At the outer surface r = d/2, so τ_max = 16T/(πd³). The factor of 16 follows directly from combining these two expressions.

Question 28Engineering Fundamentals and Applied Science

A particle moves in a straight line with velocity given by v = 3t² m/s. Starting from rest at the origin at t = 0, what distance has it travelled at t = 2 s?

  1. 12 m
  2. 8 m Correct answer.
  3. 6 m
  4. 4 m

Explanation

Distance is the integral of velocity with respect to time: s = ∫3t² dt = t³. Evaluating from 0 to 2 s gives 2³ = 8 m. Differentiating velocity instead of integrating would give acceleration and a wrong answer.

Question 29Engineering Fundamentals and Applied Science

Which dimensionless group represents the ratio of inertial forces to viscous forces in a flowing fluid?

  1. Prandtl number
  2. Nusselt number
  3. Reynolds number Correct answer.
  4. Froude number

Explanation

The Reynolds number, Re = ρVD/μ, compares inertial to viscous effects and determines whether flow is laminar or turbulent. The other groups compare different transport mechanisms and are used for heat transfer, thermal boundary layers, and free-surface flows respectively.

Question 30Engineering Fundamentals and Applied Science

A copper rod and an aluminum rod of identical length and cross-section are joined end to end. If copper has roughly twice the thermal conductivity of aluminum, what fraction of the total temperature drop occurs across the aluminum rod when steady heat flows axially?

  1. About two-thirds Correct answer.
  2. About one-third
  3. About one-quarter
  4. About one-half

Explanation

In series conduction the heat flux is the same through both rods, so the temperature drop across each is proportional to its thermal resistance L/(kA). Since the aluminum conductivity is about half that of copper, its resistance is about twice as large, giving it roughly two-thirds of the total drop.

Question 31Engineering Fundamentals and Applied Science

A beam of monochromatic light passes from air into glass with a refractive index of 1.5. Which property of the light remains unchanged on entering the glass?

  1. Speed
  2. Frequency Correct answer.
  3. Direction of propagation
  4. Wavelength

Explanation

Frequency is set by the source and is conserved across a dielectric interface. The speed drops to c/n and the wavelength shortens in proportion, which is why the ray bends according to Snell's law when it enters at an angle.

Question 32Engineering Fundamentals and Applied Science

A DC series motor is connected to a constant supply voltage. If its mechanical load is removed so that the armature current falls sharply, what happens to the motor speed?

  1. It falls toward zero
  2. It stays constant at rated speed
  3. It rises to a dangerously high value Correct answer.
  4. It reverses direction

Explanation

In a series motor the flux is proportional to armature current, so the back-emf relation E = V − I_aR_a implies speed rises sharply as the current and flux fall. With no load the current becomes very small and the speed can reach destructive levels, which is why series motors are never started unloaded.

Question 33Engineering Fundamentals and Applied Science

A 10 kΩ resistor and a 10 µF capacitor are connected in series across a 12 V DC source, initially uncharged. What is the time constant of the circuit?

  1. 1 s
  2. 10 s
  3. 0.01 s
  4. 0.1 s Correct answer.

Explanation

The RC time constant is τ = RC = 10,000 Ω × 10 × 10⁻⁶ F = 0.1 s. After one time constant the capacitor reaches about 63 percent of the applied voltage.

Question 34Engineering Fundamentals and Applied Science

A 50 Hz, 400 V three-phase induction motor runs at a slip of 4 percent. What is its rotor speed?

  1. 1500 rpm
  2. 1380 rpm
  3. 1560 rpm
  4. 1440 rpm Correct answer.

Explanation

Synchronous speed for a 4-pole machine at 50 Hz is 120f/p = 1500 rpm. Rotor speed is N_s(1 − s) = 1500 × 0.96 = 1440 rpm. Slip always reduces rotor speed below synchronous speed in motoring operation.

Question 35Engineering Fundamentals and Applied Science

A binary alloy of composition 30 wt% B is held at a temperature in the two-phase region where the liquid composition is 50 wt% B and the solid composition is 10 wt% B. What fraction of the alloy is liquid, by the lever rule?

  1. 0.75
  2. 0.20
  3. 0.25
  4. 0.50 Correct answer.

Explanation

The lever rule gives the liquid fraction as (C_alloy − C_solid)/(C_liquid − C_solid) = (30 − 10)/(50 − 10) = 0.50. The tie line ends are the equilibrium compositions of the two coexisting phases, not the overall composition.

Question 36Engineering Fundamentals and Applied Science

In a simple ideal Rankine cycle, which process occurs in the boiler?

  1. Isentropic compression of the working fluid
  2. Isentropic expansion of the working fluid
  3. Constant-pressure heat rejection
  4. Constant-pressure heat addition to the working fluid Correct answer.

Explanation

In the boiler the working fluid receives heat at essentially constant pressure, converting subcooled liquid into saturated or superheated steam. The turbine handles isentropic expansion, the condenser rejects heat, and the pump performs isentropic compression.

Question 37Engineering Fundamentals and Applied Science

A 2 kg block slides down a frictionless incline of height 5 m starting from rest. Taking g as 9.81 m/s², what is its speed at the bottom?

  1. 9.9 m/s Correct answer.
  2. 14.0 m/s
  3. 7.0 m/s
  4. 49.0 m/s

Explanation

Energy conservation gives ½mv² = mgh, so v = √(2gh) = √(2 × 9.81 × 5) ≈ 9.9 m/s. The mass cancels, and on a frictionless incline the result is independent of the slope angle.

Question 38Engineering Fundamentals and Applied Science

A closed-loop system has an open-loop transfer function L(s) = K/(s(s+2)(s+5)). Using the Routh-Hurwitz criterion, what is the maximum value of K for which the closed-loop system remains stable?

  1. 70 Correct answer.
  2. 10
  3. 140
  4. 35

Explanation

The characteristic equation is s³ + 7s² + 10s + K = 0. Routh-Hurwitz requires all coefficients positive and 7 × 10 > K, so stability holds for 0 < K < 70. At K = 70 the system sits on the imaginary axis with a pair of pure imaginary roots.

Question 39Engineering Fundamentals and Applied Science

A stepped shaft has a 40 mm diameter section rigidly joined to a 20 mm diameter section, and equal torques are transmitted through both. What is the ratio of maximum shear stress in the smaller section to that in the larger section?

  1. 16
  2. 8 Correct answer.
  3. 2
  4. 4

Explanation

For torsion, τ_max is proportional to 1/d³ because τ = 16T/(πd³). Halving the diameter therefore raises the stress by a factor of 2³ = 8, which is why diameter changes dominate torsional stress concentrations.

Question 40Engineering Fundamentals and Applied Science

In a vapor-compression refrigeration cycle, a refrigerant enters the compressor as saturated vapor at 200 kPa and leaves at 800 kPa. Which assumption is standard when modelling the compressor ideally for a first-law analysis?

  1. The compression is isothermal
  2. The compression is isentropic Correct answer.
  3. The compression occurs at constant volume
  4. The compression is isenthalpic

Explanation

An ideal compressor is treated as adiabatic and reversible, so the process is isentropic and the exit state is fixed by inlet entropy and discharge pressure. Real compressors have irreversibility, giving higher exit entropy and a larger work input.

Question 41Engineering Design and Analysis

In a chemical process design, a control valve fails closed on loss of instrument air. Which failure mode does this describe, and what is the primary design intent behind it?

  1. Fail-indeterminate action chosen so the valve holds its last position regardless of air loss
  2. Fail-lock action chosen so the valve requires manual reset before any movement occurs
  3. Fail-open action chosen so the valve always vents the line to atmosphere on air loss
  4. Fail-safe action chosen so the valve moves to the position that protects the process when the actuating energy is lost Correct answer.

Explanation

A fail-safe position is selected so that loss of motive power (instrument air) drives the valve to a position that protects equipment, product, and personnel. The chosen position depends on the process hazard, and for many feed or fuel lines the protective position is closed.

Question 42Engineering Design and Analysis

A piping and instrumentation diagram uses the tag FT-101 with a signal line to FIC-101. What do the letters FT signify in this tag?

  1. Flow totalizer
  2. Field terminal
  3. Filter trip
  4. Flow transmitter Correct answer.

Explanation

In ISA-style instrument tagging, the first letter denotes the measured variable (F for flow) and the succeeding letters denote the function (T for transmitter). A transmitter converts the measured variable into a standard signal for the controller.

Question 43Engineering Design and Analysis

A centrifugal pump is specified for a duty point of 50 m3/h at 40 m head. Which statement correctly describes how the operating point is established?

  1. It is the flow at which the pump motor reaches its nameplate current
  2. It is the shutoff head of the pump at zero flow
  3. It is the point of maximum efficiency on the pump curve regardless of the system
  4. It is the intersection of the pump characteristic curve with the system resistance curve Correct answer.

Explanation

The operating point is where the head the pump can deliver equals the head the system requires at the same flow. It is found graphically or numerically at the intersection of the pump curve and the system curve.

Question 44Engineering Design and Analysis

During a hazard review, a team asks what would happen if a level controller output signal were lost while the inlet valve is air-to-open. Which analysis technique is specifically structured to trace this deviation from design intent?

  1. Bow-tie analysis linking threats and consequences to a central event
  2. HAZOP using guide words applied to process parameters Correct answer.
  3. Fault tree analysis starting from a defined top event
  4. Layer of protection analysis scoring independent protection layers

Explanation

HAZOP systematically applies guide words to process parameters to identify deviations from design intent and their causes and consequences. Signal loss on a controller is a classic cause examined under deviations such as no flow or wrong flow.

Question 45Engineering Design and Analysis

A pressure vessel shell is designed under ASME Section VIII Division 1 rules. Which document establishes the maximum allowable working pressure basis and required thickness for the cylindrical shell?

  1. The manufacturer's standard catalog rating for similar vessels
  2. The hydrostatic test pressure alone, since it bounds all operating conditions
  3. The applicable construction code formulas for the selected material and joint efficiency Correct answer.
  4. The purchaser's preferred operating pressure with no code calculation

Explanation

Code construction rules give thickness and pressure formulas that incorporate design pressure, allowable stress, corrosion allowance, and joint efficiency. The maximum allowable working pressure follows from those calculations for the chosen material and weld details.

Question 46Engineering Design and Analysis

A heat exchanger is being sized for a duty of 500 kW with a log mean temperature difference of 25 K and an overall coefficient of 400 W/(m2 K). What approximate area is required?

  1. 80 m2
  2. 125 m2
  3. 20 m2
  4. 50 m2 Correct answer.

Explanation

Using Q = U A LMTD, the area is 500000 divided by (400 times 25), which equals 50 square meters. This basic sizing relationship assumes a clean, well-mixed duty with the stated overall coefficient.

Question 47Engineering Design and Analysis

A distillation column is designed with a reflux ratio well above minimum. What is the principal trade-off of increasing reflux ratio?

  1. Column diameter decreases while reboiler duty stays constant
  2. Product purity falls because of reduced vapor traffic
  3. Fewer theoretical stages are needed, but reboiler and condenser duties increase Correct answer.
  4. More theoretical stages are needed, and reboiler duty decreases

Explanation

Raising reflux ratio moves operation away from minimum reflux, reducing the number of equilibrium stages required for a given separation. The cost is higher boilup and condensation, which increases energy demand and can increase column diameter.

Question 48Engineering Design and Analysis

A design team must select a material for a vessel handling wet chloride service at ambient temperature. Which concern most directly governs material selection in this case?

  1. Stress corrosion cracking resistance of the candidate alloy Correct answer.
  2. Electrical conductivity of the wetted surface
  3. Color and surface finish of the external coating
  4. Thermal expansion coefficient matching to the support steel

Explanation

Wet chlorides are a well-known cause of stress corrosion cracking in susceptible stainless steels, so alloy selection is driven by resistance to that mechanism. Other properties matter but are secondary to the governing degradation mode.

Question 49Engineering Design and Analysis

A relief valve on a reactor is sized for a runaway reaction scenario. Which basis should the designer use to establish the required relief rate?

  1. The maximum flow of the utility steam supply
  2. The peak rate of pressure-generating energy release from the credible worst-case upset Correct answer.
  3. The design flow of the downstream flare header
  4. The normal operating vapor rate at steady state

Explanation

Relief sizing for reactive systems must be based on the maximum credible rate of energy release and the resulting vapor or two-phase generation during the upset. Normal steady-state rates are not bounding for a runaway scenario.

Question 50Engineering Design and Analysis

A shell-and-tube exchanger must handle a severely fouling tube-side fluid. Which configuration choice best supports cleaning and maintenance?

  1. U-tube bundle with the fouling fluid on the shell side
  2. Fixed tubesheet with removable channel covers and straight tubes Correct answer.
  3. Double-pipe exchanger with welded tube ends
  4. Spiral-wound exchanger with no mechanical access to the tube circuit

Explanation

Straight tubes with removable heads permit mechanical cleaning of the tube interior and access to both tube ends. Putting the fouling stream in the tubes makes cleaning easier than shell-side fouling, which is harder to reach.