BE/B Eng Bachelor of Engineering Mechanical Engineering 2 — Questions and Answers
Question 1: What is the purpose of a Bourdon tube in engineering instruments?
- To measure fluid pressure (Correct answer)
- To measure fluid flow rate
- To measure temperature
- To measure viscosity
Correct answer: To measure fluid pressure
A Bourdon tube is a curved metallic tube that straightens under internal pressure, with its deflection used to measure gauge pressure in fluid systems.
Question 2: In gear systems, the gear ratio is defined as the ratio of the number of teeth on the:
- Driven gear to the driving gear (Correct answer)
- Driving gear to the driven gear
- Smallest gear to the largest gear
- Output shaft speed to input shaft speed
Correct answer: Driven gear to the driving gear
Gear ratio = teeth on driven gear / teeth on driving gear, and inversely equals the input-to-output speed ratio for a simple gear pair.
Question 3: Which heat transfer mechanism does not require a medium and can occur in a vacuum?
- Radiation (Correct answer)
- Conduction
- Convection
- Advection
Correct answer: Radiation
Thermal radiation transfers energy via electromagnetic waves and requires no medium, making it the only mode that works through a vacuum.
Question 4: What is the function of a check valve in a hydraulic system?
- To allow flow in only one direction (Correct answer)
- To regulate flow rate
- To reduce pressure surges
- To filter contaminants
Correct answer: To allow flow in only one direction
A check valve (non-return valve) permits fluid flow in one direction only and automatically prevents backflow when downstream pressure exceeds upstream pressure.
Question 5: In manufacturing, what does CNC stand for?
- Computer Numerical Control (Correct answer)
- Controlled Numerical Cutting
- Coordinated Numeric Computing
- Computer Network Control
Correct answer: Computer Numerical Control
CNC (Computer Numerical Control) uses pre-programmed computer software to control the movement of machine tools like mills, lathes, and routers.
Question 6: What is cavitation in fluid machinery?
- The formation and violent collapse of vapor bubbles due to local pressure dropping below vapor pressure (Correct answer)
- The buildup of air pockets in pipelines
- The erosion of pump impellers by high-velocity flow
- The turbulent mixing of two fluid streams
Correct answer: The formation and violent collapse of vapor bubbles due to local pressure dropping below vapor pressure
Cavitation occurs when local static pressure falls below the fluid's vapor pressure, causing vapor bubbles to form and collapse violently, damaging components.
BE/B Eng Bachelor of Engineering Mechanical Engineering 2
What is the purpose of a Bourdon tube in engineering instruments?