Worksheetsscientific principles exam
Total questions: 28
Worksheet time: 14mins
Describe what a pure metal is and where the metal could be used in a plumbing situation.
A metal consisting of a single element with minimal impurities; used for copper pipe and fittings
A mixture of metals with non‑metal additives; used for brass valves only
A plastic polymer; used for PVC pipe
A ceramic compound used for bathroom tiles
What does a ferrous material contain?
Iron
Aluminium
Carbon only
Copper
What is a disadvantage of a ferrous material?
Highly resistant to rust
Lightweight compared with aluminium
Prone to rusting and corrosion
Non‑magnetic in all cases
What is an alloy?
A mixture of two or more elements with at least one metal
A single pure metal element
A ceramic formed by heating clay
A polymer made from long chains of hydrocarbons
Name two alloys used in the plumbing industry and where they may be found.
Brass in taps and valves; solder for joining copper pipe
Bronze in soil stacks; wrought iron for push‑fit joints
Aluminium in underground mains; pewter for flue liners
Titanium in waste traps; lead‑free glass for radiators
What plastic is commonly used as the underground mains and the service pipe to a property?
MDPE (medium‑density polyethylene)
PVC‑U (unplasticised PVC)
ABS (acrylonitrile butadiene styrene)
PEX (cross‑linked polyethylene)
What plastic can be used to supply hot and cold water to the draw off point inside a domestic property?
PEX (cross‑linked polyethylene)
PVC‑U (unplasticised PVC)
ABS (acrylonitrile butadiene styrene)
HDPE (high‑density polyethylene)
Which plastic is used on waste discharge branches and can be solvent welded?
PVC‑U (unplasticised PVC)
Polypropylene (PP)
Polyethylene (PE)
PEX (cross‑linked polyethylene)
What is density equal to?
Mass per unit volume
Weight per unit area
Force per unit length
Volume per unit mass
What is the relative density of water?
0.5
1
10
1000
Why will LPG sink to the floor?
It is denser than air
It is lighter than air
It chemically reacts with oxygen to form heavier gases
It sinks because it is hot
What does ductile mean?
Can be drawn out into wire without breaking
Resists corrosion in all environments
Is magnetic under normal conditions
Breaks easily under tension
Hard water is produced when rainwater falls onto which type of ground?
Limestone or chalk
Granite
Clay
Sand dunes
Where in the UK is hard water found, and how is hardness in water measured?
Mainly southern and eastern England; measured in mg/L as CaCO3 or degrees of hardness
Mostly northern Scotland; measured by pH
Primarily Wales; measured by temperature change
Uniformly nationwide; measured by turbidity
Above what temperature do calcium carbonates start to leave hard water?
30°C
60°C
90°C
100°C
When calcium carbonates begin to leave hard water, how does this affect a hot water system—pipework, cylinder, boiler and draw off points?
Limescale deposits build up, narrowing pipework, insulating heating surfaces, reducing efficiency at boiler and cylinder, and restricting draw‑off points
Metal components corrode instantly and turn water green
System pressure increases so rapidly that expansion vessels always burst
Water becomes strongly acidic and dissolves copper pipes overnight
What is the pH number for pure water?
5
7
9
14
What is a drawback of soft water?
Leaves scale rapidly on heating surfaces
Can be more corrosive to metal pipework and fittings
Increases the hardness of water
Freezes at a higher temperature than hard water
What is latent heat?
Heat absorbed or released during a change of state without a change in temperature
Visible radiant heat from a flame
Heat measured directly by a thermometer at any time
Heat produced only by chemical reactions
The water in a hot water cylinder exerts its pressure:
Downwards only
Upwards only
Downwards and sideways
Sideways only
Atmospheric pressure at sea level is:
303.1Pa
201.3Pa
101.3Pa
111.3Pa
What are the three elements of the fire triangle?
Heat
Fuel
Oxygen
Water
What is meant by the term calorific value?
The amount of heat energy released by the complete combustion of a unit mass or volume of fuel
The density of a fuel compared to water
The pressure of a gas at room temperature
The maximum flame temperature of a burner
Which of the following gases has the highest calorific value?
Propane
Butane
Natural gas
Oxygen
What gas is commonly used when soldering fittings to copper pipe?
Propane
Oxygen
Nitrogen
Carbon dioxide
Describe AC mains electricity:
Alternating current that reverses direction periodically, typically at 50 Hz, supplied by the mains
Constant‑voltage direct current produced by batteries
Static electricity stored on insulated surfaces
Three‑phase mechanical vibration transmitted through wires
How is DC electricity produced?
By chemical action in batteries or via rectifiers, producing current in one direction
By spinning magnets in generators to create alternating current
By compressing gas in cylinders
By heating resistive wires to incandescence
True or false: The anode in a battery eats away the cathode.
True
False
