Scientific Principles

Which of the following pipes, each measuring 6m in length, will offer the greatest resistance to the flow of water?

• 15mm pipe with four elbows
• 15mm pipe with four machine bends
• 22mm pipe, which reduces down to 15mm halfway along its length
• 15mm pipe with two machine bends and two elbows

What is the intensity of pressure acting at the base of a 7m long pipe, which has a head height of 3 meters (the cistern at the head of this pipe measures 500mmx 500mm x 500mm)?

• 50.4 KPa
• 29.43kPa
• 100.1 kPa
• 1000.1 kPa

Conduction occurs by:

• Heat travelling in a straight line through the air
• Heat travelling through or along a solid material
• Heat travelling via a chemical reaction
• Heat travelling via the motion of a fluid.

What is the freezing point of water at sea level?

• 100
• 15
• 0 
• 55

Which of the following materials is the best conductor of heat?

• Lead 
• Copper
• Wood
• Cast  Iron 

With a downward pressure of 100kPa and a head of 10m, what would be the approximate pressure in bar?

• 100 bar
•  1bar 
• 50 bar
• 10 bar 

What would the fuse size be for a domestic appliance that has a power rating of 3kW?

• 3 amp 
• 13 amp
• 30 amp
• 100 amp 

Which of the following values reflects the pH value for pure water?

• 1
• 4
• 7
• 10

The limescale build-up in systems is caused by:

• Soft water
• Acidic water
• Permanently hard water
• Temporary hard water

A change of state may occur when water is heated to:

• 100
• 20
• 50
• 75