FUNDAMENTALS OF THERMODYNAMICS

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• Q1: Define Thermodynamics.
  Ans: Thermodynamics is the branch of science that deals with heat, work, energy, and the relationship between them. It studies how energy is transferred and converted in different systems.
• Q2: Name the types of units.
  Ans: The types of units are:

  • ➔ Basic Units
  • ➔ Derived Units
• Q3: Define Basic Units.
  Ans: Basic units are the fundamental units which cannot be expressed in terms of other units. They form the base for all other units.
• Q4: Name some Basic Units.
  Ans: Some basic units are:

  • ➔ Meter (m)
  • ➔ Kilogram (kg)
  • ➔ Second (s)
  • ➔ Ampere (A)
  • ➔ Kelvin (K)
• Q5: Define Derived Units.
  Ans: Derived units are the units which are obtained by combining two or more basic units according to physical laws.
• Q6: Name some Derived Units.
  Ans: Some derived units are:

  • ➔ Newton (N)
  • ➔ Joule (J)
  • ➔ Watt (W)
  • ➔ Pascal (Pa)
• Q7: Name the Systems of Units.
  Ans: The systems of units are:

  • ➔ F.P.S System (Foot Pound Second System)
  • ➔ M.K.S System (Meter Kilogram Second System)
  • ➔ C.G.S System (Centimeter Gram Second System)
  • ➔ S.I Units (System of International Units)
• Q8: Define Power.
  Ans: Power is the rate of doing work. It tells how fast work is done or energy is transferred.
  Power = Work Done / Time
• Q9: Write the unit of Power.
  Ans: The SI unit of power is Watt (W). One watt is equal to one joule of work done per second.
• Q10: Define System.
  Ans: A system is a definite portion of matter or space selected for study. Everything outside the system is called surroundings.
• Q11: Define Thermodynamic System.
  Ans: A thermodynamic system is a quantity of matter or a region in space chosen for thermodynamic study where energy transfer may occur.
• Q12: State the classification of System.
  Ans: The system is classified as:

  • ➔ Closed System
  • ➔ Open System
• Q13: Define Closed System.
  Ans: A closed system is a system in which mass does not cross the boundary, but energy transfer in the form of heat or work can occur.
• Q14: Define Open System.
  Ans: An open system is a system in which both mass and energy can cross the system boundary.
• Q15: What are the Extensive properties of a system?
  Ans: Extensive properties are the properties that depend on the quantity or size of the system. Examples include mass, volume, and total energy.
• Q16: What are the Intensive properties of a system?
  Ans: Intensive properties are the properties that do not depend on the size or quantity of the system. Examples include temperature, pressure, and density.
• Q17: Define Heat.
  Ans: Heat is a form of energy that is transferred from one body to another due to temperature difference.
• Q18: Define Heat Transfer.
  Ans: Heat transfer is the movement of heat energy from a higher temperature body to a lower temperature body.
• Q19: Name the methods of Heat Transfer.
  Ans: The methods of heat transfer are:

  • ➔ Conduction
  • ➔ Convection
  • ➔ Radiation
• Q20: Define Conduction.
  Ans: Conduction is the method of heat transfer in which heat flows from one part of a body to another or from one body to another through direct contact, without movement of the particles.
• Q21: Define Convection.
  Ans: Convection is the method of heat transfer in which heat is transferred by the actual movement of fluid particles such as liquids or gases from one place to another.
• Q22: Define Radiation.
  Ans: Radiation is the method of heat transfer in which heat is transferred in the form of electromagnetic waves without the need of any material medium.
• Q23: Define Mass.
  Ans: Mass is the amount of matter present in a body. It remains constant irrespective of location.
• Q24: Define Weight.
  Ans: Weight is the force with which the earth attracts a body. It depends on gravitational acceleration.
• Q25: Define Gravitational Acceleration.
  Ans: Gravitational acceleration is the acceleration produced on a body due to the force of gravity. Its standard value on earth is 9.81 m/s².
• Q26: Define Force.
  Ans: Force is a push or pull that can change the state of rest or motion of a body. It is equal to mass multiplied by acceleration.
• Q27: Define Work.
  Ans: Work is done when a force moves a body through a certain distance in the direction of the force. The formula of Work is as under:
  Work = Force x Distance
• Q28: Define Pressure.
  Ans: Pressure is the force acting per unit area. It is equal to force divided by area.
• Q29: Define Normal Pressure.
  Ans: Normal pressure is the atmospheric pressure at sea level under normal conditions. It is equal to 1 atmosphere (1 atm) or 760 mm of mercury.
• Q30: Define Standard Pressure.
  Ans: Standard pressure is the reference pressure used for scientific calculations. It is equal to 1 atmosphere or 101.325 kPa.
• Q31: Define Atmospheric Pressure.
  Ans: Atmospheric pressure is the pressure exerted by the weight of air present in the atmosphere on the surface of the earth.
• Q32: Define Vacuum Pressure.
  Ans: Vacuum pressure is the pressure below atmospheric pressure. It shows how much the pressure is less than the surrounding atmospheric pressure.
• Q33: Define Absolute Zero Pressure.
  Ans: Absolute zero pressure is the pressure measured from absolute vacuum. At this condition, there is no pressure because no molecules are present.
• Q34: Define Absolute Pressure.
  Ans: Absolute pressure is the total pressure measured from absolute zero pressure. It is equal to atmospheric pressure plus gauge pressure.
• Q35: Define Gauge Pressure.
  Ans: Gauge pressure is the pressure measured above atmospheric pressure. It does not include atmospheric pressure.
• Q36: Define Temperature.
  Ans: Temperature is the measure of the degree of hotness or coldness of a body. It indicates the level of heat energy present in a substance.
• Q37: Define Thermometer.
  Ans: A thermometer is an instrument used to measure the temperature of a body or substance.
• Q38: Define Gas Thermometer.
  Ans: A gas thermometer is a thermometer that measures temperature by observing the change in pressure or volume of a gas.
• Q39: Define Mercury Thermometer.
  Ans: A mercury thermometer is a thermometer that uses mercury as the working substance to measure temperature.
• Q40: Name the temperature scales.
  Ans: The temperature scales are:

  • ➔ Celsius Scale
  • ➔ Fahrenheit Scale
  • ➔ Kelvin Scale
• Q41: Define Celsius or Centigrade Scale.
  Ans: Celsius or Centigrade scale is the temperature scale in which the freezing point of water is 0°C and the boiling point is 100°C at standard atmospheric pressure.
• Q42: Define Kelvin Scale.
  Ans: Kelvin scale is the absolute temperature scale in which 0 K represents absolute zero temperature. It is used in scientific calculations.
• Q43: Define Fahrenheit Scale.
  Ans: Fahrenheit scale is the temperature scale in which the freezing point of water is 32°F and the boiling point is 212°F at standard atmospheric pressure.
• Q44: Define Absolute Temperature.
  Ans: Absolute temperature is the temperature measured from absolute zero on the Kelvin scale.
• Q45: Define Normal Temperature.
  Ans: Normal temperature is the ordinary temperature of surroundings, generally taken as 0°C for reference in calculations.
• Q46: Define Standard Temperature.
  Ans: Standard temperature is the reference temperature used in scientific work, usually taken as 0°C or 273 K.
• Q47: Write the units of the followings.
  Ans:

  Measuring Unit	F.P.S	M.K.S	S.I
  Force	Pound (lb)	Kilogram-force (kgf)	Newton (N)
  Distance	Foot (ft)	Meter (m)	Meter (m)
  Time	Second (s)	Second (s)	Second (s)
  Work	Foot-pound (ft·lb)	Kilogram-meter (kg·m)	Joule (J)
  Velocity	Foot per second (ft/s)	Meter per second (m/s)	Meter per second (m/s)
  Acceleration	Foot per second² (ft/s²)	Meter per second² (m/s²)	Meter per second² (m/s²)
  Power	Horsepower (HP)	Kilogram-meter per second (kg·m/s)	Watt (W)

• Q48: Define Energy.
  Ans: Energy is the capacity of a system to do work. It can exist in various forms such as heat, mechanical, chemical, or electrical energy.
• Q49: Name the types of energy found in the system.
  Ans: The types of energy are:

  • ➔ Stored Energy
  • ➔ Transit Energy
• Q50: Define Stored Energy.
  Ans: Stored energy is the energy contained within a system at a given instant. It includes potential energy, kinetic energy, and internal energy.
• Q51: Define Transit Energy.
  Ans: Transit energy is the energy that crosses the boundary of a system in the form of work or heat during a process.
• Q52: Define Potential Energy.
  Ans: Potential energy is the energy possessed by a body due to its position or configuration relative to a reference point.
• Q53: Define Kinetic Energy.
  Ans: Kinetic energy is the energy possessed by a body due to its motion. It is proportional to the mass and square of velocity of the body.
• Q54: Define Internal Energy.
  Ans: Internal energy is the energy stored within a system due to the random motion and interactions of its molecules.
• Q55: State the laws of Thermodynamics.
  Ans: The laws of thermodynamics include: Zeroth Law, First Law, Second Law, and Third Law. These laws govern the behavior of energy, heat, and work in a system.
• Q56: Define Zeroth Law of Thermodynamics.
  Ans: Zeroth Law of Thermodynamics states that if two systems are in thermal equilibrium with a third system, then they are in thermal equilibrium with each other.
• Q57: Define First Law of Thermodynamics.
  Ans: The First Law of Thermodynamics states that energy can neither be created nor destroyed; it can only be transformed from one form to another. The change in internal energy equals heat added minus work done by the system.
• Q58: State the limitations of First Law of Thermodynamics.
  Ans: The First Law does not indicate the direction of energy transfer and cannot predict whether a process will occur spontaneously. It only quantifies energy changes.
• Q59: Define Second Law of Thermodynamics.
  Ans: The Second Law of Thermodynamics states that heat cannot spontaneously flow from a colder body to a hotter body, and all natural processes increase the entropy of the universe.
• Q60: What is Kelvin-Planck Statement?
  Ans: Kelvin-Planck Statement states that it is impossible to construct a heat engine that converts all the heat absorbed from a source into work without any other effect.
• Q61: What is Clausius Statement?
  Ans: Clausius Statement states that it is impossible for a process to transfer heat from a colder body to a hotter body without doing external work.
• Q62: State the Law of Conservation of Energy.
  Ans: The Law of Conservation of Energy states that the total energy of an isolated system remains constant; energy can change form but the total amount does not change.
• Q63: State the Law of Conservation of Matter.
  Ans: The Law of Conservation of Matter states that matter can neither be created nor destroyed in a chemical reaction; the total mass remains constant.
• Q64: What is the formula of Horse Power in M.K.S?
  Ans: Its formula is:
• Q65: What is the formula of Horse Power in F.P.S?
  Ans: Its formula is:
• Q66: What is the formula of Power in S.I?
  Ans: Its formula is: