Scientific Principles

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

• a.    15mm pipe with four elbows

• a.    15mm pipe with four machine bends

• a.    22mm pipe, which reduces down to 15mm halfway along its length

• a.    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 500mm x 500mm x 500mm)?

• a.    19.81kPa

• a.    24.67kPa

• a.    29.43kPa

• a.    32.49kPa.

Conduction occurs by:

• a.    Heat travelling in a straight line through the air

• a.    Heat travelling through or along a solid material

• a.    Heat travelling via a chemical reaction

• a.    Heat travelling via the motion of a fluid.

What is the freezing point of water at sea level?

• a.    100⁰C

• a.    75⁰C

• a.    25⁰C

• a.    0⁰C.

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

• a.    Lead

• a.    Low carbon steel

• a.    Copper

• a.    Cast iron.

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

• a.    100 bar

• a.    50 bar

• a.    10 bar

• 1 bar

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

• a.    13 amp

• a.    10 amp

• a.    5 amp

• a.    3 amp.

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

• a.    1

• a.    4

• a.    7

• a.    11.

The limescale build-up in systems is caused by:

• a.    Soft water

• a.    Acidic water

• a.    Temporary hard water

• a.    Permanently hard water.

The SI unit for measuring electrical current is:

• a.    Watt

• a.    Ampere

• a.    Joule

• a.    Ohm.