PIPE Elements 6

A substance which has a fixed chemical composition through out is called a
a. simple substance
b. pure substance
c. vapor substance
d. none of these

A liquid which is about to vaporize is called a
a. subcooled liquid
b. saturated vapor
c. saturated liquid
d. none of these

The temperature during the entire phase-change process demains constant if the pressure
a. increase
b. decrease
c. remains constant
d. none of these

A vapor which is about to condense is called a
a. saturated vapor
b. saturated liquid
c. superheated vapor
d. none of these

A vapor which is not about to condense is called a
a. mixture of vapor and liquid
b. critical vapor
c. superheated vapor
d. none of these

The temperature at which water starts boiling depends on the ________

therefore

At a given pressure

At a given temperature

The atmospheric pressure and boiling temperature of water decreases with
a. power
b. density
c. elevation
d. none of these

Is the point at which the saturated liquid and saturated vapor are identical

The critical point temperature of water is
a. 386.34⁰C
b. 374.14⁰C
c. 398.45⁰C
d. none of these

The critical pressure of water is
a. 20MPa
b. 22Mpa
c. 28Mpa
d. none of these

The critical specific volume of air is
a. 0.003155 m³/kg
b. 0.004566 m³/kg
c. 0.006567 m³/kg
d. none of these

Liquid-vapor region is also known as
a. subcooled region
b. superheated region
c. wet region
d. none of these

Passing from the solid phase directly into vapor phase is called
a. condensation
b. fusion
c. sublimation
d. none of these

Phase diagram of pure substance is
a. H-s diagram
b. T-s diagram
c. P-T diagram
d. none of these

Enthalpy of vaporization represents the amount of energy needed to vaporize a unit mass of saturated liquid at a given
a. temperature or pressure
b. specific volume
c. enthalpy
d. none of these

Enthalpy of vaporization decreases as the temperature or pressure increases

The_______is the ratio of mass of vapor to the total mass of mixture
a. moisture
b. quality
c. mixture
d. none of these

The quality of a system consists of saturated liquid is
a. zero
b. 1
c. unity
d. none of these

The quality of a system consisting of saturated vapor is
a. 0%
b. 50%
c. 100%
d. none of these

During the __________

Any equation that relates the pressure

Robert Boyle observed during his experiments with a vacuum chamber that the pressure of gases is inversely proportional to their
a. temperature
b. pressure
c. volume
d. none of these

At low pressures and high temperatures

The deviation from ideal-gas behavior at a given temperature and pressure can accurately be accounted for by the introduction of a correction factor called
a. expansion factor
b. gaseous factor
c. compressibility factor
d. none of these

Is the ratio of actual specific volume to the ideal specific volume
a. expansion factor
b. gaseous factor
c. compressibility factor
d. none of these

At very low pressure

At high temperature ideal gas behavior can be assumed with good accuracy regardless of
a. temperature
b. pressure
c. volume
d. none of these

The deviation of a gas from ideal gas behavior is greatest in the vicinity of the
a. sublimation point
b. saturation poiny
c. critical point
d. none of these

________intended to improve the ideal-gas equation of state by including two of the effects not considered in the ideal gas model with constant a and b
a. Chatle's law
b. Boyle's law
c. Van der Waal's
d. none of these

First law of thermodynamics is the law of
a. conservation of momentum
b. conservation of energy principle
c. conservation of energy interaction
d. none of these

States that during an interaction between a system and its surroundings

Heat is the form of energy that is transferred between two systems by virtue of
a. temperature difference
b. pressure difference
c. volume difference
d. none of these

______is energy in transition
a. heat
b. work
c. power
d. none of these

A process during which there is no heat transfer is called an
a. isochoric process
b. hyperbolic process
c. adiabatic process
d. none of these

Is the transfer of energy from the more energetic oarticles of a substance to thw adjacent less energetic ones as a result of interaction between particles.
a. conduction
b. convection
c. radiation
d. none of these

________of the material is a measure of the ability of a material to conduct heat.
a. convection
b. thermal radiation
c. thermal conductivity
d. none of these

Indicates that the rate of heat conduction in a direction is proportional to the temperature gradient in that direction
a. Farad's law
b. Newton's law
c. Fourier's law
d. none of these

Heat is conducted in the direction of
a. increasing temperature
b. decreasing temperature
c. decreasing pressure
d. none of these

Temperature gradient becomes negative when temperature decreases with
a. increasing temperature
b. increasing area
c. increasing wall thickness
d. none of these

Is a measure of kinetic energies of the molecules
a. temperature
b. pressure
c. volume
d. none of these

Is the mode of energy transfer between a solud surface and the adjacent liquid or gas which is in motion

The faster the fluid motion

If the fluid is forced to flow in a tube or over a surface by external means
a. natural convection
b. force convection
c. free convection
d. none of these

If the motion is caused by bouyancy forces which are induced by the density differences due to the vibration of temperature in the fluid
a. Free convection
b. natural convection
c. forced convection
d. none of these

________which involve changes of phase of a fluid are also considered to be convection because of the fluid motion introduced during the process.
a. Heat transfer process
b. adiabatic process
c. cooling process
d. none of these

The rate of heat transfer by convection is deteined from
a. Fourier's law of cooling
b. Newton's law of cooling
c. Charle's law of cooling
d. none of these

Is the energy emitted by matter in the form of electromagnetic waves as a result of the changes in the electronic configurations of the atoms or molecules.
a. radiation
b. conduction
c. convection
d. none of these

Energy transfer by radiation is fastest and it suffers no attenuation in
a. positive pressure
b. maximum pressure
c. a vacuum
d. none of these

Which if the form of radiation emitted by bodies because of their temperature
a. convection
b. conduction
c. thermal radiation
d. none of these

Is a volumetric phenomenon

Radiation is usually considered as
a. surface phenomenon
b. surface interaction
c. surface corrosion
d. none of these

The maximum rate of radiation which can be emitted from a surface at an absolute temperature is given by
a. Stefan-Boltzmann law
b. Newton's law
c. Maxwell's law
d. none of these

The idealized surface which emits radiation at this maximum rate is called
a. blue body
b. reservoir
c. black body
d. none of thess

The radiation emitted by black body is called a
a. black body radiation
b. white body radiation
c. blue body radiation
d. none of these

All bodies at a temperature above absolute zero emit
a. thermal convection
b. thermal radiation
c. thermal conduction
d. none of these

The velocity of fluid in a pipe is ________at the wall
a. zero
b. one
c. infinity
d. none of these

The velocity of fluid at the center of pipe is
a. maximum
b. minimum
c. allowable minimum
d. none of these

kirchhof's law of radiation states that the emissivity and the absorptivity of a surface are equal at the same temperature and
a. Mach number
b. velocity
c. wavelength
d. none of these

The difference between the rates of radiation emitted by the surface and the radiation absorbed is the
a. natural convection
b. net radiation heat transfer
c. heat added
d. none of these

Work is__________between the system and the surroundings
a. work interaction
b. energy interaction
c. heat interaction
d. none of these

Energy can cross the system by means of
a. pressure
b. energy
c. heat and work
d. none of these

If the energy crossing the boundary of a closed system is not heat

The driving force of heat is the
a. thickness
b. area
c. temperature difference
d. none of these

is the energy transfer associated with a force acting through a distance
a. energy
b. work
c. power
d. none of these

The work per unit time is called
a. energy
b. work
c. power
d. none of these

Work done by a system is
a. positive
b. negative
c. zero
d. none of these

Work done on a system is
a. positive
b. negative
c. zero
d. none of these

the work produced by car engines

Work consumed by compressors

The energy of a system decreases
a. as it does work
b. as it does energy
c. as it doea power
d. none of these

The energy of a system increases as work is
a. done by the system
b. done on the system
c. cross the system
d. none of these

One form of mechanical work frequently encountered in practice is associated with the expansion or compression of a gas in a
a. screw device
b. hydraulic device
c. piston-cylinder device
d. none of these

The expansion and compression work is often called
a. steady boundary work
b. moving boundary work
c. critical work
d. none of these

is a process during which the system remains in equilibrium at all times.
a. Quasi-equilibrium
b. static equilibrium
c. dynamic equilibrium
d. none of these

The volume change is positive during an expansion process and negative during a
a. expansion process
b. compression process
c. steady flow process
d. none of these

The area under the process curve on a P-V diagram is equal to
a. heat
b. work done
c. power
d. nobe of these

Is the work done by or against a gravitational force field.
a. Gravitational work
b. Impact work
c. kinetic work
d. none of these

The work associated with a change in velocity of a system is called
a. speed work
b. acceleration work
c. work combination
d. none of these

the power transmitted by the shaft is the shaft work per
a. mass of flow
b. volume flow
c. unit time
d. nine of these

The microscopic force are perpendicular to any line in the surface

Electrical work-the force is
a. current
b. voltage
c. battery
d. none of these

First law of thermodynamics is known as the
a. conservation of electrons
b. conservation of atoms
c. conservation of energy
d. none of these

States that energy can neither be created nor destroyed
a. First law of thermodynamics
b. Second law of thermodynamics
c. Third law of thermodynamics
d. none of these

A major consequence of the first law is the existence and the definition of the property is
a. total work
b. total heat
c. total energy
d. none of these

In the absence of any work interactions between a system and its surroundings

For________

Is the energy storage capabilities of the substance
a. specific heat
b. specific heat ratio
c. diabatic
d. none of these

Specifuc heat is the energy required to raise the temperature of a unit mass of a substance by
a. one degree
b. two degree
c. three degree
d. none of these

Constant volume specific heat is the energy required to raise the temperature of a unit mass by one degree as the volume is
a. increase
b. decrease
c. maintained constant
d. none of these

The specific heats of real gas at low pressure are called ideal-gas specific heats or
a. zero pressure specific heats
b. zero temperature specific heats
c. non-zero specific heats
d. none of these

The specific heat varies with
a. temperature
b. specific volume
c. pressure
d. none of these

A substance whose specific volume(or density) is constant is called
a. compressible substance
b. incompressible substance
c. compressible gas
d. none of these

The constant volume and constant pressure specific heats are identical for
a. compressible substance
b. incompressible substance
c. compressible gas
d. none of these

The energy requirements of a body is met by the
a. water we drink
b. meat we eat
c. food we eat
d. none of these

the boundaries of a control volume are called a
a. control volume
b. control boundary
c. control surface
d. none of these

Control volume can be fixed in
a. pressure
b. temperature
c. size and shape
d. none of these

The term steady implies
a. no change with time
b. change with time
c. change with velocity
d. none of these

The term uniform implies no change with location over a
a. specified region
b. specified space
c. specified entropy
d. none of these