Question Number 31:
What is absolute humidity?
Option A: The temperature to which humid air must be cooled at constant pressure to become saturated.
Option B: The actual amount of the water vapour in a mixture of air and water.
Option C: The ratio of the water vapour actually present in the atmosphere to the amount that would be present if the air were saturated at the prevailing temperature and pressure.
The ratio of the water vapour actually present in the atmosphere to the amount that would be present if the air were saturated at the prevailing temperature and pressure.
Absolute Humidity is the actual amount of water vapor in a liter of gas.
Question Number 32:
The temperature to which humid air must be cooled at constantpressuretobecome saturated is called
Option A: relative humidity.
Option B: dew point.
Option C: absolute humidity.
The temperature to which humid air must be cooled to become saturated is called the 'due point'.
Question Number 33:
Density changes with altitude at a rate
Option A: of 2kg/m3 per 1000 ft.
Option B: which changes with altitude.
Option C: which is constant until 11 km.
which changes with altitude.
The rate of change of density is not constant - it diminishes with altitude. So no single figure for lapse rate can be quoted.
Question Number 34:
Above 65,800 ft temperature,
Option A: decreases by 1.98°C up to 115,000 ft.
Option B: remains constant up to 115,000 ft.
Option C: increases by 0.303°C up to 115,000 ft.
increases by 0.303°C up to 115,000 ft.
65,800ft is the upper stratosphere boundary. Temperature increases with altitude in the stratosphere.
Question Number 35:
At sea level, ISA atmospheric pressure is
Option A: 14.7 kPa.
Option B: 10 Bar.
Option C: 14.7 PSI.
An alternative to 1013.2mb.
Question Number 36:
On a very hot day with ambient temperature higher than ISA, the pressure altitude is 20,000 ft. How much will the density altitude be?
Option A: the same.
Option B: greater than 20,000ft.
Option C: less than 20,000ft.
greater than 20,000ft.
Density Altitude is pressure altitude corrected for temperature and humidity. Assuming constant humidity, ISA or above temperature will further thin the air for a given pressure altitude thus making the density altitude higher.
Note: At ISA Temp density and pressure altitude will be the same and for less than ISA, density altitude will be less
Question Number 37:
The atmospheric zone where the temperature remains fairly constant is called the
Option A: Stratosphere.
Option B: Ionosphere.
Option C: Troposphere.
The stratosphere starts at 36,000ft and rises to about 66,000ft.
Question Number 38:
In the ISA the height of the tropopause is
Option A: 11,000 feet.
Option B: 11,000 metres.
Option C: 36,000 metres.
11,000 metres or 36,000 feet approximately.
Question Number 39:
In the ISA the sea level pressure is taken to be
Option A: 14 PSI.
Option B: 1013.2 mb.
Option C: 1.013 mb.
Question Number 40:
In the ISA, the temperature lapse rate with altitude is taken to be
Option A: dependent on pressure and density changes.
Option B: linear.
Option C: non linear.