EIT Electrical, Thermodynamics & Fluid Systems — Questions and Answers
Question 1: What is the primary unit of electric current?
- Volt
- Ohm
- Ampere (Correct answer)
- Watt
Correct answer: Ampere
The Ampere (A) is the primary and base SI unit of electric current. It quantifies the rate of flow of electric charge through a conductor. Other options like Volt (unit for electric potential difference), Ohm (unit for electrical resistance), and Watt (unit for power) are related but measure different electrical quantities.
Question 2: What does the first law of thermodynamics state?
- Energy is always lost in a system.
- Energy can be created from nothing.
- Energy is conserved and changes form (Correct answer)
- Work and heat are unrelated.
Correct answer: Energy is conserved and changes form
The first law of thermodynamics, also known as the Law of Conservation of Energy, states that energy cannot be created or destroyed in an isolated system. Instead, it can only be transformed from one form to another, such as from potential energy to kinetic energy or from chemical energy to heat. This fundamental principle underpins all energy transformations in physical and chemical processes.
Question 3: What type of fluid flow has layers sliding past each other smoothly?
- Turbulent flow
- Laminar flow (Correct answer)
- Oscillating flow
- Vacuum flow
Correct answer: Laminar flow
Laminar flow is a type of fluid motion characterized by smooth, parallel layers of fluid that slide past each other without significant mixing. This occurs at low Reynolds numbers, where viscous forces dominate inertial forces. In contrast, turbulent flow involves chaotic, irregular fluid motion with eddies and vortices.
Question 4: What device is used to measure electric potential difference?
- Ammeter
- Ohmmeter
- Voltmeter (Correct answer)
- Galvanometer
Correct answer: Voltmeter
A voltmeter is an instrument specifically designed to measure the electric potential difference, or voltage, between two points in an electrical circuit. It is connected in parallel across the components where the voltage measurement is desired. Ammeters measure current, ohmmeters measure resistance, and galvanometers detect small currents.
Question 5: In thermodynamics, what does entropy represent?
- Energy content
- System mass
- Heat transfer rate
- Degree of disorder (Correct answer)
Correct answer: Degree of disorder
In thermodynamics, entropy is a measure of the disorder or randomness within a system. The second law of thermodynamics states that the total entropy of an isolated system can only increase over time, or remain constant in ideal cases. This means that systems naturally tend towards states of greater disorder and energy dispersal.
Question 6: What is Bernoulli’s equation used to describe?
- Heat transfer
- Electrical resistance
- Fluid flow and pressure changes (Correct answer)
- Entropy balance
Correct answer: Fluid flow and pressure changes
Bernoulli's equation is a fundamental principle in fluid dynamics that describes the relationship between pressure, velocity, and height in a moving fluid. It states that for an incompressible, inviscid fluid in steady flow, an increase in fluid speed must be accompanied by a decrease in pressure or a decrease in the fluid's potential energy. This equation is widely used in engineering to analyze and design systems involving fluid flow, such as aircraft wings and pipelines.
Question 7: Which law defines the relationship between voltage, current, and resistance?
- Faraday’s Law
- Newton’s Law
- Ohm’s Law (Correct answer)
- Kirchhoff’s Law
Correct answer: Ohm’s Law
Ohm's Law is a fundamental principle in electrical engineering that defines the direct relationship between voltage (V), current (I), and resistance (R). It states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them (V = IR). This law is crucial for analyzing and designing electrical circuits.
Question 8: What is the typical unit of viscosity in SI?
- Newton
- Watt
- Pascal-second (Correct answer)
- Joule
Correct answer: Pascal-second
Viscosity is a measure of a fluid's resistance to flow. In the International System of Units (SI), the standard unit for dynamic viscosity is the pascal-second (Pa·s). This unit is equivalent to newton-second per square meter (N·s/m²), representing the shear stress required to produce a unit shear rate.
Question 9: Which thermodynamic cycle is most commonly used in power plants?
- Otto cycle
- Carnot cycle
- Rankine cycle (Correct answer)
- Brayton cycle
Correct answer: Rankine cycle
The Rankine cycle is the thermodynamic cycle that most accurately models the process by which steam-turbine systems generate power in thermal power plants. It describes the conversion of heat energy into mechanical work through a working fluid, typically water, undergoing phase changes (evaporation and condensation). While the Carnot cycle represents the theoretical maximum efficiency, the Rankine cycle is a practical and widely implemented power generation cycle.
EIT Electrical, Thermodynamics & Fluid Systems
What is the primary unit of electric current?