MECHANICAL ENGINEERING MCQ SECTION 32

311. The hot tearing in a metal casting is due to

(A) High fluidity

(B) High melt temperature

(C) Wide range of solidification temperature

(D) Low coefficient of thermal expansion

Answer: -Wide range of solidification temperature

312. Cutting tool is much harder than the workpiece. Yet the tool wears out during the tool-work interaction, because

(A) Extra hardness is imparted to the workpiece due to coolant used

(B) Oxide layers on the workpiece surface impart extra hardness to it

(C) Extra hardness is imparted to the workpiece due to severe rate of strain

(D) Vibration is induced in the machine tool.

Answer: -Extra hardness is imparted to the workpiece due to severe rate of strain

313. A minimal spanning tree in network flow models involves

(A) All the nodes with cycle/loop allowed

(B) All the nodes with cycle/loop not allowed

(C) Shortest path between start and end nodes

(D) All the nodes with directed arcs

Answer: -All the nodes with cycle/loop not allowed

314. The process utilizing mainly thermal energy for removing material is

(A) Ultrasonic Machining

(B) Electrochemical Machining

(C) Abrasive Jet Machining

(D) Laser Beam Machining

Answer: -Laser Beam Machining

315. There is no work transfer involved in this process

(A) Adiabatic expansion

(B) Isothermal expansion

(C) Polytropic expansion

(D) Free expansion

Answer: -Free expansion

316. This process is one in which there is only work interaction between the system

and the surroundings

(A) Diabetic process

(B) Adiabatic process

(C) Isothermal process

(D) Quasi-static process

Answer: -Adiabatic process

317. In which of the following processes, the heat is fully converted into work?

(A) Reversible adiabatic process

(B) Reversible isobaric process

(C) Reversible isometric process

(D) Reversible isothermal process

Answer: -Reversible isothermal process

318. Consider the following statements for a throttling process.

1. It is an adiabatic process

2. There is no work transfer in the process

3. Entropy increases in throttling process

Which of these statements are correct?

(A) 1,2 and 3 (B) 1 and 2 only

(C) 2 and 3 only (D) 1 and 3 only

Answer: -1,2 and 3

319. In case of free vibrations with viscous damping, the damping force is proportional to

(A) The displacement

(B) The velocity

(C) The acceleration

(D) The natural frequency

Answer: -The velocity

320. The critical speed of shaft depends on

(A) Mass only

(B) Stiffness only

(C) Mass and Stiffness

(D) Mass, Stiffness and Eccentricity

Answer: -Mass and Stiffness