Question Number 11:

Question Number 11:

As altitude increases, pressure

Option A: decreases exponentially.

Option B: decreases at constant rate.

Option C: increases exponentially.

__Correct Answer:__

decreases exponentially.

__Explanation:__

As altitude increases, pressure decreases exponentially. Since pressure is given by density * gravity * height, both density and height decreases (that is, height above the point you measuring) so the decrease in pressure is exponential.

__Question Number 12:__

Lapse rate usually refers to

Option A: Density.

Option B: Pressure.

Option C: Temperature.

__Correct Answer:__

Temperature.

__Explanation:__

Temperature lapse rate is constant up to 36000ft -2degrees per 1000ft.

__Question Number 13:__

Temperature above 36,000 feet will

Option A: increase exponentially.

Option B: decrease exponentially.

Option C: remain constant.

__Correct Answer:__

remain constant.

__Explanation:__

Temperature lapse rate up to 36,000 feet (the tropopause) is approximately 2 degrees centigrade per 1000 feet. Above the tropopause it is constant.

__Question Number 14:__

With increasing altitude pressure decreases and

Option A: temperature decreases at the same rate as pressure reduces.

Option B: temperature decreases but at a lower rate than pressure reduces.

Option C: temperature remains constant to 8000 ft.

__Correct Answer:__

temperature decreases but at a lower rate than pressure reduces.

__Explanation:__

See a graph of pressure against altitude and temperature against altitude. Pressure decreases faster than temperature therefore pressure has a greater effect upon the performance of the aircraft.

__Question Number 15:__

What is the temperature in comparison to ISA conditions at 30,000ft?

Option A: -60°C.

Option B: 0°C.

Option C: -45°C.

__Correct Answer:__

-45°C.

__Explanation:__

ISA = 15°C temperature lapse rate is 2°C per 1000ft. Therefore 30000 = - 60 +15 = -45.

Question Number 16:

Question Number 16:

At what altitude is the tropopause?

Option A: 36,000 ft.

Option B: 57,000 ft.

Option C: 63,000 ft.

__Correct Answer:__

36,000 ft.

__Explanation:__

The tropopause is 36,000 ft. Above the tropopause is the stratosphere.

__Question Number 17:__

What approximate percentage of oxygen is in the atmosphere?

Option A: 12%.

Option B: 21%.

Option C: 78%.

__Correct Answer:__

21%.

__Explanation:__

21% oxygen, 78% nitrogen, 1% other gases.

__Question Number 18:__

Which has the greater density?.

Option A: Air at low altitude.

Option B: Air at high altitude.

Option C: It remains constant.

__Correct Answer:__

Air at low altitude.

__Explanation:__

Air density reduces with altitude.

__Question Number 19:__

At what altitude does stratosphere commence approximately?

Option A: Sea level.

Option B: 36,000 ft.

Option C: 63,000 ft.

__Correct Answer:__

36,000 ft.

__Explanation:__

The stratosphere is above 36,000 ft.

__Question Number 20:__

A pressure of one atmosphere is equal to

Option A: 14.7 psi.

Option B: 1 inch Hg.

Option C: 100 millibar.

__Correct Answer:__

14.7 psi.

__Explanation:__

One atmosphere is 14.7 psi.

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