Polytechnic Engineering Fundamentals 2 — Questions and Answers
Question 1: What is the First Law of Thermodynamics?
- Energy cannot be created or destroyed, only converted (Correct answer)
- Heat flows from cold to hot
- Entropy always increases in an isolated system
- Work is the product of force and displacement
Correct answer: Energy cannot be created or destroyed, only converted
The First Law of Thermodynamics is the conservation of energy: total energy in a closed system remains constant.
Question 2: What is the SI unit of power?
- Watt (W) (Correct answer)
- Joule (J)
- Newton (N)
- Pascal (Pa)
Correct answer: Watt (W)
Power is measured in watts (W), where 1 watt equals 1 joule per second.
Question 3: What does Kirchhoff's Current Law (KCL) state?
- The sum of currents entering a node equals the sum of currents leaving it (Correct answer)
- Voltage is the same across all parallel branches
- Total resistance in series is the sum of individual resistances
- Power dissipated equals current squared times resistance
Correct answer: The sum of currents entering a node equals the sum of currents leaving it
KCL states that current is conserved at any node — what flows in must flow out.
Question 4: Which material property describes resistance to plastic deformation?
- Hardness (Correct answer)
- Toughness
- Ductility
- Brittleness
Correct answer: Hardness
Hardness is a material's resistance to permanent (plastic) deformation, often measured by indentation tests.
Question 5: What is the purpose of a capacitor in a circuit?
- To store electrical energy in an electric field (Correct answer)
- To convert AC to DC
- To amplify electrical signals
- To regulate current flow
Correct answer: To store electrical energy in an electric field
A capacitor stores electrical energy in the electric field between its two conductive plates.
Question 6: What is the formula for kinetic energy?
- KE = ½mv² (Correct answer)
- KE = mv
- KE = mgh
- KE = ½mv
Correct answer: KE = ½mv²
Kinetic energy is ½mv², where m is mass and v is velocity.
Polytechnic Engineering Fundamentals 2
What is the First Law of Thermodynamics?