BE/B Eng Bachelor of Engineering Bachelor of Engineering Science 2 — Questions and Answers
Question 1: Which dimensionless number represents the ratio of inertial forces to viscous forces in fluid flow?
- Froude number
- Reynolds number (Correct answer)
- Mach number
- Euler number
Correct answer: Reynolds number
The Reynolds number (Re = ρvL/μ) determines whether flow is laminar or turbulent by comparing inertial to viscous forces.
Question 2: In digital logic, what is the output of a NAND gate when both inputs are HIGH?
- HIGH
- LOW (Correct answer)
- Undefined
- Floating
Correct answer: LOW
A NAND gate outputs LOW only when all inputs are HIGH; it is the complement of an AND gate.
Question 3: Which material property describes resistance to permanent deformation under stress?
- Toughness
- Ductility
- Hardness (Correct answer)
- Resilience
Correct answer: Hardness
Hardness measures a material's resistance to surface indentation or permanent deformation, commonly tested via Vickers or Rockwell methods.
Question 4: What is the primary purpose of a flywheel in a mechanical system?
- Increase torque output
- Store rotational kinetic energy (Correct answer)
- Reduce friction losses
- Change gear ratios
Correct answer: Store rotational kinetic energy
A flywheel stores rotational kinetic energy (KE = ½Iω²) to smooth out fluctuations in angular velocity.
Question 5: In thermodynamics, a Carnot cycle operating between 600 K and 300 K has a maximum theoretical efficiency of:
- 25%
- 33%
- 50% (Correct answer)
- 75%
Correct answer: 50%
Carnot efficiency = 1 − T_cold/T_hot = 1 − 300/600 = 0.50 or 50%.
Question 6: Which structural analysis method satisfies both equilibrium and compatibility conditions?
- Method of sections
- Force method
- Finite element method (Correct answer)
- Graphical statics
Correct answer: Finite element method
The finite element method satisfies both equilibrium (force balance) and compatibility (displacement continuity) through variational formulations.
Question 7: In control systems, the steady-state error for a unit ramp input applied to a Type-1 system equals:
- Zero
- 1/Kv (Correct answer)
- 1/Ka
- Infinity
Correct answer: 1/Kv
A Type-1 system has one integrator; its steady-state ramp error is 1/Kv where Kv is the velocity error constant.
BE/B Eng Bachelor of Engineering Bachelor of Engineering Science 2
Which dimensionless number represents the ratio of inertial forces to viscous forces in fluid flow?