DC Boiler Exam Prep 2023 (Formulas and constants used
for the DC 3rd class boiler exam) QUESTIONS WITH
COMPLETE SOLUTIONS (2024/
2025)
1.Area of a rectangle: Length x Width
2.Area of a Circle: .7854 x Diameter²
3.Volume of a Box: Length x Width x Height
4.Volume of a Cylinder: .7854 x Diameter² x Length
5.Circumference of a Circle: Àx Diameter
6.Unit of Force: Pound (lb)
7.Formula for Force: Pressure ÷ Area
8.Unit of Work: in-lb or ft-lb
,9.Formula for Work: Force x Distance
10.Unit of Power: ft-lb/min
11.Formula for Power: = Work
÷ Time or (Force x Distance) ÷
Time
12.Formula for Mechanical Horsepower: = Power ÷ 33,000 ft-lb/min
13.Fahrenheit to Celsius: °C = (°F - 32) ÷ 1.8
14.Celsius to Fahrenheit: °F = (1.8 x °C) - 32
15.Fahrenheit to Rankine: °R = °F + 460
16.Celsius to Kelvin: K = °C +273.15
17.Charles' First Law: Volume1 / Pressure1 = Volume2 / Pressure2
18.Charles' Second Law: Pressure1 / Temperature1 = Pressure2 /
Temperature2
,19.Boyle's Law: Pressure1 x Volume1 = Pressure2 x Volume2
20.General Gas Law: (Pres1 x Vol1)/ Temp1 = (Pres2 x Vol2)/Temp2
21.Formula for Levers: Resistance x DistanceR = Effort x DistanceE
22.Formula for Inclined Planes: Force x Length = Resistance x Heigh
23.Formula for Wheel & Axel: Force x DistanceF = Resistance x
DistanceR
24.Torque: Force x Radius
25.Safe Working Pressure of a Riveted Boiler (SWP): (Area of
Staybolt x Stress Constant of Staybolt) ÷ Area Covered by Staybolt or =
(a x C) ÷ A
26.Area Covered by Staybolt: = Pitch x Pitch
27.Longitudinal Stress: (P x D x
L) / 2t P = Pressure
, D=
Diameter L
= Length
t = thickness of steel
28.Boiler Heating Surface (tubes) =: =
C x L x # C = Circumference of tubes
L = Length of
tubes # =
Number of tubes
HS = Àx Diameter x Length x Number of Tubes
29.Watts per Boiler Horsepower: 746 Watts
for the DC 3rd class boiler exam) QUESTIONS WITH
COMPLETE SOLUTIONS (2024/
2025)
1.Area of a rectangle: Length x Width
2.Area of a Circle: .7854 x Diameter²
3.Volume of a Box: Length x Width x Height
4.Volume of a Cylinder: .7854 x Diameter² x Length
5.Circumference of a Circle: Àx Diameter
6.Unit of Force: Pound (lb)
7.Formula for Force: Pressure ÷ Area
8.Unit of Work: in-lb or ft-lb
,9.Formula for Work: Force x Distance
10.Unit of Power: ft-lb/min
11.Formula for Power: = Work
÷ Time or (Force x Distance) ÷
Time
12.Formula for Mechanical Horsepower: = Power ÷ 33,000 ft-lb/min
13.Fahrenheit to Celsius: °C = (°F - 32) ÷ 1.8
14.Celsius to Fahrenheit: °F = (1.8 x °C) - 32
15.Fahrenheit to Rankine: °R = °F + 460
16.Celsius to Kelvin: K = °C +273.15
17.Charles' First Law: Volume1 / Pressure1 = Volume2 / Pressure2
18.Charles' Second Law: Pressure1 / Temperature1 = Pressure2 /
Temperature2
,19.Boyle's Law: Pressure1 x Volume1 = Pressure2 x Volume2
20.General Gas Law: (Pres1 x Vol1)/ Temp1 = (Pres2 x Vol2)/Temp2
21.Formula for Levers: Resistance x DistanceR = Effort x DistanceE
22.Formula for Inclined Planes: Force x Length = Resistance x Heigh
23.Formula for Wheel & Axel: Force x DistanceF = Resistance x
DistanceR
24.Torque: Force x Radius
25.Safe Working Pressure of a Riveted Boiler (SWP): (Area of
Staybolt x Stress Constant of Staybolt) ÷ Area Covered by Staybolt or =
(a x C) ÷ A
26.Area Covered by Staybolt: = Pitch x Pitch
27.Longitudinal Stress: (P x D x
L) / 2t P = Pressure
, D=
Diameter L
= Length
t = thickness of steel
28.Boiler Heating Surface (tubes) =: =
C x L x # C = Circumference of tubes
L = Length of
tubes # =
Number of tubes
HS = Àx Diameter x Length x Number of Tubes
29.Watts per Boiler Horsepower: 746 Watts
