DC Boiler Exam Prep 2023 (Formulas and constants used for the DC 3rd class boiler exam) QUESTIONS WITH COMPLETE SOLUTIONS.

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