Fundamentals of Engineering Fundamentals of Engineering MCQ 3 — Questions and Answers
Question 1: Which of the following is the correct expression for the efficiency of a Carnot heat engine operating between a hot reservoir at T_H and a cold reservoir at T_C (temperatures in Kelvin)?
- η = T_C / T_H
- η = 1 − T_H / T_C
- η = 1 − T_C / T_H (Correct answer)
- η = (T_H − T_C) / T_C
Correct answer: η = 1 − T_C / T_H
Carnot efficiency is η = 1 − T_C/T_H, where temperatures must be in absolute (Kelvin) units.
Question 2: A steel rod 2 m long with cross-sectional area 0.001 m² is subjected to a tensile force of 100 kN. If E = 200 GPa, what is the elongation?
- 0.5 mm
- 1.0 mm (Correct answer)
- 2.0 mm
- 0.1 mm
Correct answer: 1.0 mm
δ = FL/(AE) = 100,000×2/(0.001×200×10⁹) = 200,000/200,000,000 = 0.001 m = 1.0 mm.
Question 3: In digital logic, what is the output of a 3-input AND gate when inputs are A=1, B=0, C=1?
- 0 (Correct answer)
- 1
- Undefined
- Depends on gate type
Correct answer: 0
An AND gate outputs 1 only when ALL inputs are 1; since B=0, the output is 0.
Question 4: Which law states that the pressure of a fixed amount of gas is inversely proportional to its volume at constant temperature?
- Charles's Law
- Gay-Lussac's Law
- Boyle's Law (Correct answer)
- Avogadro's Law
Correct answer: Boyle's Law
Boyle's Law states P ∝ 1/V at constant temperature: P₁V₁ = P₂V₂.
Question 5: A projectile is launched horizontally from a height of 20 m. Ignoring air resistance and using g = 10 m/s², how long does it take to reach the ground?
- 1 s
- 2 s (Correct answer)
- 4 s
- √2 s
Correct answer: 2 s
h = ½gt² → 20 = ½×10×t² → t² = 4 → t = 2 s.
Question 6: In chemical engineering, what does the term 'steady-state' mean for a process?
- All flows are zero
- System properties do not change with time (Correct answer)
- The system is in chemical equilibrium
- Temperature is uniform throughout
Correct answer: System properties do not change with time
Steady-state means all system properties (temperature, pressure, composition) remain constant over time, though flows may be nonzero.
Question 7: What is the determinant of the 2×2 matrix [[3, 5], [2, 4]]?
- 2 (Correct answer)
- 12
- 22
- −2
Correct answer: 2
det = (3×4) − (5×2) = 12 − 10 = 2.
Fundamentals of Engineering Fundamentals of Engineering MCQ 3
Which of the following is the correct expression for the efficiency of a Carnot heat engine operating between a hot reservoir at T_H and a cold reservoir at T_C (temperatures in Kelvin)?