plumbing science Flashcards
what is voltage
The unit for electromotive force
What is resistance
The ohm is the unit of resistance which opposes the flow of current
what is watts
Watts is the unit of power for an appliance
If an appliance needs 3kw in a domestic property what is the fuse size?
3,000 divided by 230=13 amp
what is joules
joules is the unit of electrical energy. Today it would be measured in kilo watts an hour.
what is the volts in a domestic property
230/240 volts
An appliance has a 5 amp fuse and needs 1.2kw of power. What is the voltage required?
1200 divided by 5=240v
in a domestic property an appliance has a fuse size of 3 amp.What is the maximum power rating of the appliance?
230 times 3=240w
What would be the resistance of a domestic appliance if the fuse size was 3amp?
240 divided by 3=80ohms
What is the fuse size for a domestic appliance which has 1200 ohms resistance?
240 divided by 1,200=0.2
what does DC stand for?
direct current from battery’s
what does AC stand for?
alternating current from mains
why is a TNS circuit separate?
A TNS circuit is separate because they all come in at different points
Why is a TNC circuit combined?
a TNC circuit is combined because the Earth wire is connected to the neutral wire
TT circuit is
different because your earth doesn’t connect to the electrical supply
in a hydraulic system, pressure is generally measured in wich unit?
Pascals
what is the primary difference between force and pressure?
Force is measured in newtons
pressure is measured in pascals
what role do fluids play in a hydraulic system?
they transfer force through pressurised liquid
why is stainless steel preferred over other metals for plumbing in areas prone to corrosion?
it is highly resistant to rust and corrosion
In a mechanical engineering system what does the term “velocity” refer to?
speed of an object in a specific direction
In MES why is it crucial to understand the concept of toque?
it measures the force causing rotation
which property measures a materials resistance to being deformed?
Hardness
what material is commonly used for modern residential water supply pipes due to its resistance to corrosion and ease of instillation?
PVC (polyvinyl chloride)
which plumbing material is proffered for waste, drain and vent piping due to its durability and lightweight properties?
ABS
WHAT IS THE sI base unit for length?
metre
How many pascals are equivalent to 1 bar of pressure?
100,000 pa
which property measures the resistance of a material to deformation or bending?
Hardness
What is the specific heat capacity of water?
4.19kj/kg degrees
which plastic is used for underground cold water mains?
MDPE
What happens to water when it freezes?
its density decreases
what is the process of water changing directly from ice to vapor called?
sublimation
which type of plastic becomes brittle in freezing temperatures?
Thermoplastics
which law explains that pressure exerted on a confined fluid is distributed evenly?
pascals law
The resistance of a material to being stretched or pulled
Tensile strength
Which law explains that as the speed of a fluid increases, its pressure decreases?
Bernoulli’s Principle
Why is it essential to account for thermal expansion in hot water systems?
To prevent damage from expansion of heated pipes
How can you convert a temperature from Celsius to kelvin?
add 273.15 to the Celsius temperature
Sensible heat is
heat that causes a change in temperature without a phase change
what unit is commonly used to measure energy?
Joule
which unit is used to measure power, specifically the rate at which energy is transferred?
Watt
Which scientific principle is used in plumbing to prevent backflow in water systems?
Atmospheric Pressure
What is the main factor that affects water pressure in a plumbing system?
Height and gravity
in a closed plumbing system, increasing the temperature of the water typically causes:
Increase in water pressure
Why are U-bends or P-traps used in plumbing systems?
To prevent sewer gases from entering buildings
best describes the function of a non-return valve in a plumbing system?
Allows water to flow in one direction only
In a heating system, why is an expansion vessel important?
It compensates for the expansion of water when heated
