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Worksheetsscience revision 23/24
Total questions: 1
Worksheet time: 33mins
1
Why should a temporary earth bond be fitted before cutting into any metallic pipework?
To prevent water leakage
To maintain the earth continuity
To measure the pipe's diameter
To check the water pressure
How long should the clamps of a temporary earth bond be left in place?
Until the pipework is replaced
Until the pipework is tested for leaks
Until the permanent electrical continuity is re-established
Until the temporary earth bond is no longer needed
What must all circuits and appliances be protected by according to modern regulations?
An RCD only
A fuse or MCB
A fuse or MCB and an RCD
Isolation switch
Where is permanent de-commissioning done?
At the appliance
At the consumer unit
At the main switch
At the circuit breaker
What is required for every circuit and appliance for safety?
Where can temporary de-commissioning be done?
At the consumer unit
At the main switch
At the appliance
At the circuit breaker
What does the symbol with a straight line on top of a dashed line represent in electrical diagrams?
AC symbol
Ground connection
DC symbol for rectified current
DC symbol for battery
What does the symbol with a sine wave inside a circle represent in electrical diagrams?
AC symbol
DC symbol for rectified current
DC symbol for battery
Ground connection
Which symbol represents a battery in electrical diagrams?
AC symbol
Ground connection
DC symbol for rectified current
DC symbol for battery
What does the 'W' in the power triangle represent?
Watts
Volts
Amps
Ohms
What does the 'A' in the power triangle stand for?
Watts
Volts
Amps
Joules
What does the 'V' in the power triangle symbolize?
Watts
Volts
Amps
Resistance
How much power is required from the immersion heater to heat 250 liters of water by 55°C in one hour?
5.9 kW
15.9 kW
25.9 kW
35.9 kW
What is the formula to calculate the volume of a cylinder?
Radius + Radius + Height
Radius x Radius x Height
3.14 x Radius sq x Height
3.14 x Radius + Height
What is the temperature difference required to heat the water from 10°C to 60°C?
40°C
50°C
60°C
70°C
What is the specific heat capacity of water used in the calculation?
3.14 kJ/kg°C
4.18 kJ/kg°C
50 kJ/kg°C
36.784 kJ/kg°C
How much heat is required to raise the temperature of 176 litres of water by 50°C?
36,784 kJ
17,600 kJ
4,180 kJ
50 kJ
What is the formula to calculate the quantity of water in litres for a cylindrical tank?
Quantity of water = Radius x Height
Quantity of water = 3.14 x Radius x Height
Quantity of water = Diameter x Height
Quantity of water = 2 x Radius x Height
What is the temperature difference required to heat the water from 10°C to 60°C?
40°C
50°C
60°C
70°C
How much heat is required to raise the temperature of 176 litres of water by 50°C?
36,784 kJ
35,000 kJ
37,000 kJ
40,000 kJ
What is the specific heat capacity of water used in the calculation?
3.14 kJ/kg°C
4.18 kJ/kg°C
4.50 kJ/kg°C
5.00 kJ/kg°C
How many joules are required to heat 1 gram of water by 1 °C?
1 Joule
4.18 Joules
1000 Joules
0.418 Joules
What is the Specific Heat capacity of water commonly measured in?
Grams
Kilograms
Litres
Cubic meters
How much does 1 litre of water at 4°C weigh?
1 gram
100 grams
1 kg
10 kg
What is the formula to calculate the heat required to raise the temperature of water?
Heat required = Quantity of water (litres) x Δt
Heat required = Quantity of water (litres) x Δt x 4.18
Heat required = Quantity of water (kg) x Δt x 4.18
Heat required = Quantity of water (kg) x Δt
Which of the following are methods by which heat can be transferred?
Conduction
Compression
Convection
Radiation
Where is the fulcrum located in a first class lever?
At one end
In the middle
On the effort side
On the resistance side
Which of the following is an example of a first class lever?
Wheelbarrow
Bottle opener
Crowbar
Nutcracker
What is the resistance of a 15mm elbow
0.5m
0.6m
4.0m
2.5m
What is the resistance of the pipework if you use machine bends?
0.5m
0.6m
4.0m
0.3m
What is the weight of a litre of water at its most dense state?
0.5 Kg
1 Kg
1.5 Kg
2 Kg
What is the SI unit of velocity?
Newtons
Metres per second
Pascal
Litres per second/minute
How is force measured in the SI unit system?
Metres per second squared
Litres per second/minute
Newtons
Pascal
What is the SI unit for pressure?
Metres per second
Newtons
Pascal
Litres per second/minute
Which of the following is the SI unit for acceleration?
Metres per second
Metres per second squared
Newtons
Pascal
What does the SI unit 'l/s or l/m' stand for?
Velocity
Force
Pressure
Flow rate
What is the SI unit of length?
Kilogram
Second
Meter
Ampere
What is the symbol for the SI unit of mass?
s
A
m
Kg
Which base quantity is measured in seconds?
Length
Time
Electric current
Thermodynamic temperature
What is the SI unit for thermodynamic temperature?
Kelvin
Meter
Kilogram
Second
What is the symbol for the SI unit of electric current?
K
s
A
m
What are the three components needed to create fire according to the principles of combustion?
Fuel, Oxygen, Water
Fuel, Hydrogen, Heat
Fuel, Oxygen, Heat
Oxygen, Heat, Spark
What is the result of combining Propane, Oxygen, and a spark?
Explosion
Fire
Flame
Smoke
Combustion is described as a chemical reaction with which element?
Hydrogen
Carbon Dioxide
Oxygen
Nitrogen
According to the document, fire is one of the most destructive elements that exist.
True
False
What is the pH value of pure water according to the pH scale
5
6
7
8
On the pH scale, which range is indicated as acidic?
1-5
6-7
8-12
0-6
What potential problem is associated with acidic water in plumbing?
Limescale
Blocking
Corrosion and pitting
Increased efficiency
What is the pH range for alkaline (hard) water
1-5
6-7
8-12
0-6
Which of the following issues can arise from alkaline water in plumbing systems?
Corrosion and pitting
Limescale, blocking less efficient
Increased flow rate
Decreased water temperature
What is the main cause of temporary hard water?
CO2 in the air
Limestone and chalk (calcium carbonate)
Salt (calcium sulphate)
Sandstone (CO2 retained)
At what temperature does temporary hard water form limescale?
25°C
45°C
65°C
85°C
What is the impact of limescale on appliances?
Improves efficiency
No impact
Reduces efficiency
Changes the color of appliances
What happens to water when sensible heat is applied to it?
It changes from water to steam.
It remains water and the temperature rises.
It immediately freezes.
It becomes a gas without a temperature change.
At what temperature does water need to be raised to change from water to steam?
0°C
50°C
100°C
150°C
What is the process called when a liquid turns into a gas?
Freezing
Melting
Condensing
Vaporizing
