BE/B Eng Bachelor of Engineering Mechanical Engineering

Question 1

Which law of thermodynamics states that energy cannot be created or destroyed, only converted from one form to another?

Accepted Answer

First Law

Answer

The First Law of Thermodynamics is the law of energy conservation: the total energy of an isolated system remains constant.

Question 2

What does the second law of thermodynamics imply about the entropy of an isolated system?

Accepted Answer

Entropy always increases or remains constant

Answer

The Second Law states that the entropy of an isolated system tends to increase over time, indicating the direction of spontaneous processes.

Question 3

In stress-strain analysis, Young's Modulus is defined as the ratio of:

Accepted Answer

Stress to strain in the elastic region

Answer

Young's Modulus (E) = σ/ε, where σ is axial stress and ε is axial strain, applicable within the linear elastic region of a material.

Question 4

What is the efficiency of an ideal Carnot heat engine operating between temperatures T_H = 600 K and T_C = 300 K?

Accepted Answer

50%

Answer

Carnot efficiency η = 1 - T_C/T_H = 1 - 300/600 = 0.50, or 50%; no real engine can exceed this limit between these temperatures.

Question 5

Which type of stress acts perpendicular to the cross-sectional area of a member?

Accepted Answer

Normal stress

Answer

Normal stress (σ = F/A) acts perpendicular (normal) to the cross-section, either as tension (pulling) or compression (pushing).

BE/B Eng Bachelor of Engineering Practice Test