GMJ 6035 Scientific

Which one of the following is the freezing point of water?

• 0°C.

• 32°C.

• 75°C.

• 100°C.

A change of state in water takes place at which of the following temperatures?

• 25°C.

• 50°C.

• 75°C.

• 100°C.

Water is at its maximum density at which one of the following temperatures?

• 0°C.

• 4°C.

• 25°C.

• 52°C.

Which one of the following pipes of equal length will create the greatest resistance to the flow of water?

• A 22mm pipe which reduces down to 15mm for a quarter of its length.

• A 15mm pipe which contains 4 machine bends.

• A 15mm pipe which contains 2 machine bends and 2 elbows.

• A 15mm pipe which contains 4 elbows.

Which one of the following types of device is used to take temperature measurements of pipe surfaces when commissioning a central heating system?

• Cylinder thermostat.

• Room thermostat.

• Differential digital thermometer.

• Multi-meter.

What is the amount of heat energy required to raise 200 litres of water from 10°C to 60°C, if the specific heat capacity of water is 4.2 kJ/kg/°C?

• 42000kJ.

• 50400kJ.

• 84000kJ.

• 96000kJ.

Conduction occurs by

• heat travelling in straight lines through air

• heat travelling through a solid material

• heat transfer by a chemical reaction

• heat transfer by motion of a fluid.

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

• Copper.

• Lead.

• Low carbon steel.

• Iron.

Which one of the following values reflects a neutral pH?

• 1.

• 4.

• 7.

• 11.

Lime-scale in hot water is caused by

• soft water

• temporarily hard water

• permanently hard water

• distilled water