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CHAPTER 19: RECENT BE QUESTIONS

Total questions: 105

Worksheet time: 53mins

Name
Class
Date
1.

A pump with capacity Q1 and head H1 is in series with another pump with capacity Q2 and head H2. What is the head developed if Q2 is less than Q1?

a)

2 H2 H1

b)

H2 + H1

c)

H2 / H1

d)

H2H1

2.

At ordinary temperature what substance will behave as inert gas and will not react in the combustion process?

a)

nitrogen

b)

sulfur

c)

hydrogen

d)

carbon

3.

Which of the following cycles is ideal for spark-ignition reciprocating engine?

a)

Diesel cycle

b)

Dual cycle

c)

Rankine Cycle

d)

Otto cycle

4.

What is the relative humidity when the dew point and dry bulb temperature are equal?

a)

110 %

b)

0 %

c)

100 %

d)

50%

5.

Reheating process is normally employed in steam plane when:

a)

there is excess steam

b)

subcooling is required

c)

turbine undergoes excessive moisture

d)

dehumidifying is required

6.

Where does the final removal of water vapor in an absorption refrigeration system occur?

a)

analyzer

b)

generator

c)

condenser

d)

rectifier

7.

If the average temperature liquid of power cycle during heat addition process is as high as possible, then the thermal efficiency of the cycle will:

a)

increase

b)

remain constant

c)

decrease

d)

zero

8.

What is the temperature of lubricant at which it will ignite thus limit its application?

a)

cold point

b)

burning point

c)

flash point

d)

use point

9.

What is the heat that is removed from the space to be cooled, which is the same as the heat absorbed by the cooling coils?

a)

heating capacity

b)

enthalpy

c)

work compression

d)

refrigerating effect

10.

An air conditioning system in which water is chilled or cooled and which passes the evaporator coils is:

a)

chilled water system

b)

direct expansion

c)

absorption

d)

water circulation system

11.

A multi-stage refrigeration system which is realizable in using different refrigerants is:

a)

direct

b)

cascade

c)

flooded

d)

vapor

12.

Very large pipe diameter means a thicker wall and high cost. It also means:

a)

zero pressure drop

b)

high pressure drop

c)

constant temperature

d)

low pressure drop

13.

Aside from maintaining appropriate temperature for food cold storage, how is desiccation minimized or decreased?

a)

low oxygen

b)

maintain humidity ratio

c)

low air circulation

d)

increase humidity ratio

14.

During combustion process, only limited air is supplied and not enough to supply two molecule of oxygen per one molecule of carbon, then the product is:

a)

hydration

b)

carbon monoxide

c)

carbonic acid

d)

carbon dioxide

15.

As far as combustion chamber design is considered, the maximum power output of a given engine can be increased by:

a)

increasing combustion time

b)

increasing combustion chamber volume

c)

decreasing combustion chamber volume

d)

providing small values

16.

A water conservation device which employs both air and water is condensed a condenser and cooling tower combined into one is called:

a)

shell and tube condenser

b)

air-cooled condenser

c)

water-cooled condenser

d)

evaporative condenser

17.

In order to perform efficiently, a power cycle must be communicated with the outside temperature of its surroundings and into one is called:

a)

Kirchhoff’s Law

b)

Second Law of Thermodynamics

c)

Kelvin-Planck Law

d)

First Law of Thermodynamics

18.

Water is heated in a container. It expands and becomes less dense and lighter. It rises up the container because of its reduced density and is replaced by cooler air. As this process continues, the heat is transferred and disturbed all throughout. What is this mode of heat transfer called?

a)

condenser

b)

radiation

c)

conduction

d)

convection

19.

When required, a regulator water valve in refrigerating system should be:

a)

on the suction line on compressor line

b)

in the water inlet

c)

anywhere in the system

d)

in the water outlet

20.

When there is no work between the thermodynamic system and its surrounding, the quantity of net heat transfer is equal to:

a)

total energy of an open system

b)

temperature of an open system

c)

temperature of a closed system

d)

total energy of a closed system

21.

In order to attain equilibrium in the condenser, the cooling tower range must be ____ with respect to temperature rise in the condenser.

a)

greater

b)

equal

c)

less

d)

zero

22.

If ice will form in a solution of water and salt, then it is at a temperature called:

a)

dew point

b)

freezing point depression

c)

boiling point depression

d)

critical point

23.

The flow of the convergent section of a nozzle is always subsonic. If the flow is subsonic then the Mach number is:

a)

greater than unity

b)

less than unity

c)

near than unity

d)

unity

24.

One hundred twenty percent theoretical air was supplied for combustion. What is the equivalent excess equal to:

a)

20 %

b)

100 %

c)

240 %

d)

120 %

25.

If Pi is the indicated horsepower and Pb is the indicated horsepower of a compressor, then what is mechanical efficiency, Em, equal to:

a)

Em = Pb/Pi

b)

Em = Pi/Pb

c)

Em = Pb - Pi

d)

Em = Pi - Pb

26.

What is the least number of compressor a multistage system will use?

a)

three

b)

two

c)

four

d)

one

27.

The relation between the Fahrenheit absolute scale and the Celsius absolute scale is:

a)

R = 1.8 K

b)

R = 32 °K

c)

R = 3.2 °K

d)

R = 18 °K

28.

The sum of the internal energy and the product of pressure and specific volume is known as the:

a)

enthalpy

b)

entropy

c)

total work

d)

total internal energy

29.

A refrigeration control that guards the compressor form overloads brought about by abruptly increases loads resulting from defrosting, warm products and others, is called:

a)

safety valve

b)

suction hold-back valve

c)

solenoid valve

d)

expansion valve

30.

What does fossil-fuel fired power plants release, which in turn produces the key ingredient in acid rain?

a)

nitrogen

b)

sulfur emission

c)

carbon monoxide

d)

carbon dioxide

31.

The fraction of the radiation energy incident on a surface which is absorbed by the surface is called:

a)

Convection

b)

Absorptivity

c)

Emission

d)

Radiation

32.

Which of the following power plants uses energy from uranium to produce electric power?

a)

Diesel Plant

b)

Geothermal Plant

c)

Nuclear Plant

d)

Hydroelectric Plant

33.

Ice cubes added to a glass of water and stirred. Moisture starts to form on the outer surface of the glass. At this point, what is the temperature at the outer surface called?

a)

critical temperature

b)

surface temperature

c)

dew point temperature

d)

saturation temperature

34.

The force when applied to a mass of one kilogram will give mass an acceleration of one meter per second for every second called:

a)

Watt

b)

Joule

c)

Newton

d)

Pascal

35.

The kinetic energy of a moving fluid is used to isentropically compressed the fluid to state of zero velocity. The temperature of a moving fluid at the state zero velocity is called:

a)

stagnation temperature

b)

partial temperature

c)

critical temperature

d)

absolute temperature

36.

The dew point temperature of the product of combustion in the saturation temperature that corresponds to the partial pressure of the ____ in the products.

a)

SO2

b)

H2O

c)

N2

d)

CO2

37.

What do we call a device that is used to boiler operation that will stop the burner or at least send a signal to the operator if the water drops to a low level that is no longer safe?

a)

safety valve

b)

dead-weight valve

c)

high water cut off

d)

low water cut off

38.

Dry analysis is a fractional analysis of the products of combustion which does not include:

a)

water vapor

b)

carbon dioxide

c)

sulfur dioxide

d)

carbon monoxide

39.

The size of a reciprocating pump is stamped on the builder's plate 3" × 4" × 6'. The diameter of the liquid cylinder is:

a)

5"

b)

6"

c)

3"

d)

4"

40.

One foot water is equal to:

a)

0.4318 lb/in.2

b)

68.3 lb/ft.2

c)

0.8673 lb/in.2

d)

62.43 lb/ft.2

41.

The freezing point of R-22 is:

a)

-109 °F

b)

-252 °F

c)

-256 °F

d)

-211 °F

42.

Which of the following is a type of evaporator?

a)

shell-and-tube-condenser

b)

sell-and-tube-water cooler

c)

oil lantern rings

d)

polyphase motors

43.

For Brayton cycle, the result of regeneration is:

a)

increase in thermal efficiency

b)

decrease thermal efficiency

c)

moderate thermal efficiency

d)

low thermal efficiency

44.

If the pressure exerted on a liquid is higher than the saturation corresponding to its temperature, the liquid is a:

a)

saturated liquid

b)

subcooled liquid

c)

superheated liquid

d)

highly superheated liquid

45.

In a power driven pump, each piston stroke is displaced by 360º divided the ______.

a)

revolution per minute

b)

bore

c)

length of the stroke

d)

number of cylinders

46.

If the air is compressed without discarding heat, then what do you call this kind of compression?

a)

isobaric

b)

isochoric

c)

adiabatic

d)

isothermal

47.

If a gas posses internal energy, then it is due to its;

a)

velocity

b)

pressure and volume values

c)

height from a certain datum level

d)

molecular motion

48.

The pressure of ammonia was detected in brine solution. How can ammonia be removed?

a)

freeze the brine solution

b)

heat the brine to a high temperature enough to free the ammonia

c)

throw the brine solution

d)

lower the temperature of the brine

49.

What will happen when the pressure at any point inside a centrifugal pump goes below the vapor pressure corresponding to the temperature of the liquid?

a)

turbulent flow

b)

laminar flow

c)

cavitation

d)

priming

50.

What does a negative Joule-Thompson coefficient means during a throttling process?

a)

fluid pressure is constant

b)

fluid temperature drop

c)

fluid temperature rises

d)

fluid pressure zero

51.

For steam power plants, increasing the operating pressure of the boiler will:

a)

increase thermal efficiency

b)

decrease thermal efficiency

c)

bring thermal efficiency to zero

d)

make thermal efficiency constant

52.

The ratio of the average load to that of the rated capacity of a plant is called:

a)

output factor

b)

demand factor

c)

load factor

d)

capacity factor

53.

What is the method used to evaluate all welds performed on pressure parts of boiler tube materials?

a)

hydrostatic test

b)

Orsat analysis

c)

vacuum test

d)

radiographic test

54.

If the pressure is disregarded in the various other components of a steam or gas power plants, the pressure rise in the pump or compressor is _______ to the pressure drop in the turbine.

a)

inversely proportional

b)

constant

c)

equal

d)

varying

55.

What is the effect on saturated temperature if the pressure of the fluid is decreased?

a)

there is no effect

b)

saturation temperature decreases

c)

saturation temperature remains constant

d)

saturation temperature increases

56.

If V3 is the cylinder volume after the combustion process of 8 Diesel cycle and V2 is its cylinder volume before combustion, then calculate the cut-off ratio, r.

a)

r = V3 – V2

b)

r = V2 – V3

c)

r = V2/V3

d)

r = V3/V2

57.

Compare the temperature of discharge vapor refrigerant leaving the compressor for a superheated cycle and the saturated cycle, for the same condensing temperature and pressure.

a)

there is no difference

b)

higher, for the superheated cycle

c)

higher, for the saturated cycle

d)

lower for the Superheated cycle

58.

A valve that releases steam from the boiler by opening at a pre-determined pressure in order to keep the steam pressure from rising more than the pressure from which the valve is set is called a

a)

ammonia valve

b)

stop valve

c)

check valve

d)

safety valve

59.

What is the relationship of the capacity of a centrifugal pump, Q, to impeller diameter, D, when there are two impeller diameters in the same pump?

a)

Q is directly proportional to the square of the ratio of D

b)

Q is inversely proportional to the ratio of D

c)

Q is directly proportional to the ratio of D

d)

Q is inversely proportional to the square of the ratio of D

60.

If Wt is the turbine shaft work of a gas turbine unit, Wc is its compressor shaft work and Q is the heat supplied in duel, then determine its thermal efficiency.

a)

Q / (Wt + Wc)

b)

Q / (Wt + We)

c)

(wt + We) / Q

d)

(Wt - Wc) / Q

61.

The schedule number of a pipe, N, indicates the thickness of the pipe wall. If the allowable stress of the pipe is S, then what is the internal pressure equal to?

a)

NSN - S

b)

N/SN/S

c)

N×SN\times S

d)

S/NS/N

62.

What is the pressure present inside the casing of an impulse turbine?

a)

vacuum

b)

atmospheric pressure

c)

above atmospheric

d)

zero

63.

In order to remove the fly ashes from the flue gas, which of the following must a power plant be equipped with?

a)

condenser

b)

demineralizer

c)

electrostatic precipitator

d)

desulphurization plant

64.

If Hs is the total suction head of a pump, Hp is its suction surface pressure, and Hf is its suction friction head, then calculate the total suction head, Ht.

a)

Ht = Hs - Hp - Hf

b)

Ht = Hs + Hp - Hf

c)

Ht = Hs + Hp + Hf

d)

Ht = Hs - Hp + Hf

65.

The constant spending of certain percentage of circulated water in a cooling tower in order to prevent accumulation of dissolved mineral solids and other impurities in the condenser water is called

a)

approach

b)

drift

c)

range

d)

bleed-off

66.

What process is employed when the turbine steam power plants experience excessive moisture?

a)

reheating

b)

supercooling

c)

subcooling

d)

freezing

67.

A company is interested to produce a water turbine wherein only little energy is required or necessary because the guide vanes are to be controlled. The turbine must be a:

a)

gas turbine

b)

propeller turbine

c)

Kaplan turbine

d)

Francis turbine

68.

If Et is the total net energy generated by a plant in a certain period of time and Er is the rated net energy capacity of the plant during the same period of time then what is the plant operating factor?

a)

Er - Et

b)

Et / Er

c)

Et - Er

d)

Er / Et

69.

If W is the work output of a heat engine and H is the total heat input of an engine, then determine its thermal efficiency, e.

a)

e = H/W

b)

e = W/H

c)

e = W×H

d)

e = 1 - (W - H)

70.

Which of the following is converted to mechanical energy by a water.

a)

Internal energy

b)

kinetic energy

c)

potential energy

d)

hydraulic energy

71.

What must be the value of the available Net Positive Suction Head (NPSH) of a centrifugal pump compared to its require NPSH to avoid losing priming?

a)

available NPSH lesser than required NPSH

b)

available NPSH equal than required NPSH

c)

available NPSH greater than required NPSH

d)

available NPSH constant at all times

72.

What type of fuel is used with stationary power plants where gas is available by pipeline?

a)

gaseous fuels

b)

solid fuels

c)

coal

d)

liquid fuels

73.

Wb is shaft work of an engine and Wi is the indicated work of an engine. If mechanical friction is present in the engine mechanism, then:

a)

Wb is equal to Wi

b)

Wb is less than Wi

c)

Wb is proportional to Wi

d)

Wb is greater then Wi

74.

What is the saturation pressure at the critical temperature, or the lowest pressure in which a substance can be in the liquid state at its critical pressure?

a)

external pressure

b)

critical pressure

c)

condensing pressure

d)

evaporation pressure

75.

What is the significance of a high dielectric strength of lubricating oil?

a)

oil is thick

b)

oil is contaminant-free

c)

oil is thin

d)

oil is not clean

76.

Theoretically, what is the effect of the compressor clearance on horsepower?

a)

varies in direct proportion

b)

increase power

c)

decrease power

d)

there is no effect

77.

Compare the refrigerating effect per unit mass of refrigerant circulated for a superheated cycle that produces useful cooling and a saturated cycle, for the same vaporizing and condensing temperature.

a)

lower for a superheated cycle

b)

greater for a saturated cycle

c)

the same

d)

greater for a superheated cycle

78.

It is important to take some moisture from the air to dehumidify it if the relative humidity reaches high levels. To do this, it requires cooling the air:

a)

at wet-bulb temperature

b)

above its dew point temperature

c)

at critical temperature

d)

below its dew point temperature

79.

What does enthalpy measure in a substance?

a)

its coldness

b)

its heat content

c)

its humidity

d)

its dew point

80.

Pneumatic tools are powered by:

a)

natural gas

b)

air

c)

electricity

d)

steam

81.

The pump will not cavitate if the available Net Positive Suction Head (NPSH) is:

a)

less than the required NPSH

b)

equal or lesser than the required NPSH

c)

equal or greater than the required NPSH

d)

zero compared to the required NPSH of 1

82.

A water-tube condenser has a total of 60 tubes. If these are two passes, then compute the number of tube per pass.

a)

6C

b)

15

c)

3C

d)

2

83.

If EvE_v is the volumetric efficiency of a reciprocating pump, then determine SLIP which represents all losses of capacity given in percentage of the displacement.

a)

1/Ev1/E_v

b)

11/Ev1 - 1/E_v

c)

1Ev1 - E_v

d)

Ev+1E_v + 1

84.

What is the relationship of the horsepower of a centrifugal pump, Hp, to the impeller speed, S, if the pump is at two different rotative speeds?

a)

Hp is inversely proportional to the cube of the ratio of S

b)

Hp is directly proportional to the ratio of S

c)

Hp is inversely proportional to the ratio of S

d)

Hp is directly proportional to the cube of the ratio of S

85.

What is likely to occur when sections of the impeller of a centrifugal pump are handling vapor and other sections are handling liquid?

a)

erosion of the pump

b)

high head and low capacity

c)

excessive vibration

d)

complete failure to operate

86.

When vapor compression takes place on one side of the piston and one during one revolution of the crankshaft, then the compressor is:

a)

double-acting

b)

four-cycle

c)

two-revolution

d)

single-acting

87.

In Stirling and Erickson Cycles, the efficiency can be increased by:

a)

compressibility

b)

superheating

c)

regeneration

d)

subcooling

88.

Which of the following is used to control refrigeration compressor capacity?

a)

dehumidifier

b)

check valve

c)

solenoid valve

d)

unloader

89.

During a cooling and dehumidifying process, sensible and latent heats are removed in the cooling coil. If HsH_s is the sensible heat and HtH_t is the total heat transferred, then determine the coil sensible factor.

a)

HtHsH_t - H_s

b)

HsHtH_s - H_t

c)

Ht/HsH_t/H_s

d)

Hs/HtH_s/H_t

90.

Based on PSME code, what should be provided in each stream outlets if two or more boilers will be connected in parallel?

a)

relief and check valves

b)

non-return and shut-off valves

c)

expansion and shut-off valves

d)

expansion and check valves

91.

The diesel cycle is the ideal cycle for a:

a)

absorption

b)

steam-jet

c)

compression-ignition engine

d)

gas turbine

92.

If a Carnot cycle is at the same maximum and minimum temperatures as a Rankine cycle, then how would you compare the efficiency of a Rankine cycle to that of the Carnot cycle?

a)

efficiency is the same

b)

higher efficiency

c)

efficiency is the higher, by 30%

d)

lower efficiency

93.

Compute the wall gain load of a load storage room when A is the outside surface area of the wall, D is the temperature differential across the wall, and U is the overall coefficient of heat transition.

a)

AU/DAU/D

b)

D/ND/N

c)

A/UDA/UD

d)

AUDAUD

94.

If mm is the mass of dry air and HH is the specific enthalpy of the water vapor in air and rr is the humidity ratio, then determine the latent heat of any dry air.

a)

m/(rH)m/(r - H)

b)

r/(Hm)r/(H - m)

c)

(mr)/H(m - r)/H

d)

m(r×H)m(r \times H)

95.

When an electric motor nameplate indicates a "100-kw electric motor," then what does a 100 kW rating refers to?

a)

thermal energy input

b)

thermal energy output

c)

electrical power output

d)

mechanical power output

96.

For a hydraulic power to be transmitted at its maximum what should be the value of loss of head due to friction if HH is the total available head?

a)

11H11H

b)

13H\tfrac{1}{3}H

c)

14H\tfrac{1}{4}H

d)

5H5H

97.

The ratio of the average load during a certain time to peak the load occurring during the same period of time is called:

a)

demand factor

b)

capacity factor

c)

load factor

d)

output factor

98.

Based on the PSME Code, what should be the effective temperature of the air to be maintained for comfort cooling at an air movement from 0.0761 to 0.127 meter per second?

a)

25 - 29 degrees

b)

35 - 39 degrees C

c)

20 - 24 degrees C

d)

30 - 34 degrees C

99.

Past Board Question If R is the delivery rate of a pump, H is the total pumping head and e is the efficiency of the pump, compute the power required to drive the pump.

a)

R/H×eR/H \times e

b)

1(R+H)/e1 - (R+H)/e

c)

(R×H)/e(R \times H)/e

d)

(hR)/e(h - R)/e

100.

Past Board Question There are three basic boiler types, namely:

a)

water-tube, horizontal tube and cast-iron boilers

b)

cast-iron, fire-tube and water tube boilers

c)

fire-tube, cast-steel and water tube boilers

d)

HRT, fire-tube and Marine Boilers

101.

Past Board Question The amount of heat necessary to bring up the temperature of a unit mass of a substance through a unit degree is called:

a)

specific volume

b)

thermal heat

c)

total heat

d)

specific heat

102.

Past Board Question What is the specific gravity of an oil which has a Baumé reading of 28 degrees F?

a)

0.215

b)

0.562

c)

0.886

d)

0.774

103.

Past Board Question If C is the capacity of the compressor in a refrigeration system and F is the heat rejection factor, calculate the condenser load L.

a)

L=FCL = F - C

b)

L=F/CL = F / C

c)

L=C×FL = C \times F

d)

L=C/FL = C / F

104.

Past Board Question Based on the PSME Code, what should be the humidity of air to be used for comfort cooling?

a)

75% - 80% relative humidity

b)

50% - 60% relative humidity

c)

60% - 70% relative humidity

d)

70% - 75% relative humidity

105.

Past Board Question What is the cause of pressure drop in the boiler, condenser and the pipings between different components? Because of this drop, steam leaving the boiler is at a lower pressure.

a)

positive slip

b)

fluid friction

c)

negative slip

d)

low thermal efficiency