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The CORRECT choice is (b) PV=nRT

Explanation: The IDEAL gas EQUATION is PV=ρRT, where

P=pressure of gas (Units=N/m^2)

V=volume of gas (Units=m^3)

ρ=density of gas (Units=Kg/m^3)

R=universal gas CONSTANT (Units=Nm/kg-K)

T=temperature of gas (Units=K).

Right OPTION is (a) Convective AIR flow

Explanation: The convective air flow is the major reason for the global ATMOSPHERE pressure distribution. The Coriolis forces cause the air flow to swirl and create a series of convectional current CELLS which results in the general pattern of high and low pressure region over the surface of the earth.

Correct answer is (a) An EARTH force that tends to deflect the moving objects on earth

Explanation: Coriolis force is an earth force that acts perpendicular to the direction of MOTION and to the axis of rotation. This force tends to deflect moving objects to the left in the southern HEMISPHERE and towards the RIGHT in the NORTHERN hemisphere.

Right choice is (a) 78%, 21%, 0.9%, 0.03%

The best I can EXPLAIN: The percentages of NITROGEN, oxygen, argon and CARBON dioxide in atmosphere are 78%, 21%, 0.9%, 0.03%. The atmosphere also consists of other INERT gases, dust PARTICLES, water vapor and moisture in minute quantities.

The correct CHOICE is (a) 287.05287

For EXPLANATION: The value of characteristic gas constant(R) is 287.05287 Nm/kg-K and the value of universal gas constant (R0) is 8.3145 J/mol. The RELATION between them is R=\(\frac{R0}{M}\) , where R0 is universal gas constant; R is characteristic gas constant and M is molecular WEIGHT of the SUBSTANCE.

Right option is (a) True

Explanation: Regions of LOW pressure, cyclones and HIGH pressure, anti-cyclones are formed by effects of convection currents in the atmosphere. This is caused DUE to the air transporting from higher temperature regions to the LOWER temperature regions.

The correct answer is (a) True

Easy explanation: At the equator the mean seasonal VARIATION is small and the mean TEMPERATURE is high whereas at the POLES the mean seasonal variation is LARGE and the mean temperature is LOW. This is due to the change in temperature with respect to the altitude of the atmosphere. It is almost similar to a sine graph.

The correct option is (a) 101325

The EXPLANATION is: ACCORDING to ISA ATMOSPHERIC model what is the value of datum atmospheric pressure is 101325 N/m^2. It can also be written in 1atm or 1.01325 bar or 101325 PASCAL. The conversion of N/m^2 to bar is 1 bar=10^5 N/m^2. The conversion of bar to Pascal is 1 bar=1 Pascal.

The correct answer is (c) 288.15K

Easiest EXPLANATION: According to ISA atmospheric model what is the VALUE of datum atmospheric temperature is 288.15K. It can also be written as 15.15°C. The relation between KELVIN scale and Celsius scale is K=°C+273.

Right CHOICE is (a) below 130K

To explain I would SAY: The range of temperature in mesosphere is below 130K. It starts at the top of stratosphere and ends at mesopause. It is the coldest part of EARTH’s atmosphere. It is USUALLY around 85 to 100 KILOMETERS.

Correct choice is (a) -51°Cto -15°C

Easiest explanation: The range of temperature in stratosphere is -51°Cto -15°C. The layer closer to TROPOPAUSE is -51°C and the layer close to MESOSPHERE is -15°C. This temperature change happens depending on seasonal CHANGES.

The correct choice is (c) 200-2000°C

The BEST I can explain: The range of temperature in THERMOSPHERE is 200-2000°C. The temperature VARIES from DAY and night, during night its 200°C and during day it’s 200°C. The UPPER thermosphere extends up to a temperature of 2000°C.

Right ANSWER is (a) 15°Cto -51°C

Explanation: The RANGE of temperature in troposphere is 15°Cto -51°C. Troposphere is QUITE cool compared to other atmospheric layers of earth. Troposphere has higher temperature than stratosphere.

The correct CHOICE is (b) 90KM to 500km

Easiest explanation: The altitude range of thermosphere is 90km to 500km. Thermosphere is present between MESOSPHERE and exosphere. The range of temperature in thermosphere is 200-2000°C. The temperature VARIES from day and night, during night its 200°C and during day it’s 200°C. The upper thermosphere extends up to a temperature of 2000°C.

The correct option is (c) Troposphere < Stratosphere < MESOSPHERE < Thermosphere < Exosphere

The explanation is: The correct ORDER of atmospheric layers with respect to ALTITUDE increase is troposphere < Stratosphere < Mesosphere < Thermosphere < Exosphere. The altitude range of troposphere is8km to 18km. The altitude range of stratosphere is 18km to 50KM. The altitude range of mesosphere is 50km to 85km. The altitude range of thermosphere is 90km to 500km. The altitude range of exosphere is 500km to 10000km.

The correct OPTION is (c) 50KM to 85km

Explanation: The altitude range of mesosphere is 50km to 85km. Mesosphere is PRESENT between stratosphere and THERMOSPHERE. The temperature in this region constantly decreases with increase in altitude.

The correct answer is (a) True

To explain: International STANDARD Atmosphere is based on the assumption that air is a PERFECT GAS and obeys gas law. It ALSO neglects the effects of dust, water vapour and moisture.

Correct option is (a) 1.225

Easiest explanation: According to ISA ATMOSPHERIC MODEL what is the value of datum atmospheric air DENSITY is 1.225 kg/m^3. It can also be WRITTEN as 1225 g/m^3 else 1.225 X 10^-9 kg/mm^3.

Correct answer is (a) Change of TEMPERATURE with respect to altitude

Easy explanation: Lapse RATE is the change of temperature with respect to altitude. The temperature lapse rate is linear at tropopause to STRATOSPHERE. The lapse rate is zero in from the altitude 11km to 20km. The temperature lapse rate becomes POSITIVE at the middle of stratosphere.

The correct choice is (a) ΔP=-ρg∆h

To EXPLAIN: The hydrostatic EQUATION is GIVEN by ΔP=-ρg∆h. This equation is derived from equating FORCE acting on a cylindrical flow. The unit of pressure is N/m^2. It can also be represented in atm, bar, PASCAL.

Right OPTION is (a) True

The best I can EXPLAIN: True height is the vertical geometrical distance between an OBJECT and a datum level whereas the geopotential height is the vertical coordinate referenced to earth’s mean sea level and the difference between true height and geopotential height is RELATIVELY small.

The CORRECT ANSWER is (a) True

The best explanation: Any atmosphere that does not conform to the ISA profile is REFERRED to as an off-standard atmosphere. In this atmosphere there are no ASSUMPTIONS taken as in that of ISA tables.

Right CHOICE is (a) \(\FRAC{p}{p_0}\)=[1 + \(\frac{L_0}{T_0}\)H]^\(\frac{-g_0}{RL_0}\)

Explanation: The pressure-height relationship in troposphere is given by \(\frac{p}{p_0}\)=[1 + \(\frac{L_0}{T_0}\)H]^\(\frac{-g_0}{RL_0}\) , where

p=pressure

p0=datum pressure

L0=lapse rate

T0=datum temperature

g0=acceleration due to gravity

H=height.

The CORRECT ANSWER is (B) 0.8379

The EXPLANATION is: The answer is 0.8379.

Given T=241.45K,

From relative TEMPERATURE (θ)=\(\frac{T}{T_0}\)

θ=\(\frac{241.45}{288.15}\)=0.8379.

Right OPTION is (c) 0.9435

The best I can explain: The answer is 0.9435.

Given P1600=101325 N/m^2,

From relative pressure (δ)=\(\FRAC{P_{1600}}{p_0}\)

δ=\(\frac{95602}{101325}\)=0.9435.

The CORRECT CHOICE is (a) 0.297

The explanation: The ANSWER is 0.297.

Given L0=-0.0065 K/m, T0=288.15K, P0=101325 N/m^2, H=9144m, we KNOW g0=9.81m/s^2, R=287 J/kg-K

From \(\frac{P}{p_0}\)=[1 + \(\frac{L_0}{T_0}\)H]^\(\frac{-g_0}{RL_0}\)

\(\frac{P}{P_0}\)=[1 + \(\frac{-0.0065}{288.15}\)9144]^\(\frac{-9.81}{287*-0.0065}\)

 \(\frac{P}{P_0}\)=0.297.

The correct ANSWER is (a) Airflow Direction Detector

To EXPLAIN: ADD stands for airflow direction detector. The function of airflow direction detector is to sense the local flow direction RELATIVE to the AIRCRAFT body axes and these are the part of the aircraft system.

Correct answer is (b) False

For explanation I would say: The essential requirement of air DATA MEASUREMENT is the relative motion between the aircraft and the air mass. The second essential requirement of air data measurement is the STATE of the atmosphere in which the aircraft is flying.

The CORRECT choice is (a) True

For explanation: The essential requirement of air data measurement is the state of the ATMOSPHERE in which the aircraft is FLYING. The second essential requirement of air data measurement is the relative MOTION between the aircraft and the air MASS.

The CORRECT OPTION is (b) False

Explanation: ADC is an ELECTRICAL power based system and not a pure mechanical instrument. ADC stands for air data computer. This is a device installed in aircraft to convert PRESSURE into electrical signals. The conversion is done with the help of transducers which help in PROCESSING the electrical signals.

The correct answer is (c) 0.3048

The explanation is: 1 FOOT=0.3048 meters. Foot is unit of LENGTH or distance in GENERAL SYSTEM whereas meter is a standard unit. Meter is the S.I unit of length in MKS system and USED by everyone throughout the world.

The correct answer is (a) True

Explanation: The secondary flight INSTRUMENTS are air temperature sensor and ADD’s. The ALTIMETER, INDICATOR and mach meter are the primary flight instruments. The primary instruments are mechanical instruments whereas the secondary instruments are electrical power based instruments.

The correct option is (b) 1.852

Easiest explanation: 1 knot=1.852 km/hr. Knot stands for nautical miles per hour. CONVERSION of nautical miles to KILOMETERS is 1 nautical mile=1.852km. HENCE, 1 knot=1.852 km/hr.

Right choice is (a) HEIGHT, mach number, airspeed

The best explanation: Height, mach number, airspeed are the quantities MEASURED by PITOT – static system in air data system. They CONVERT the air fed pressures into the movement of a pointer in MECHANICAL instrument.

The CORRECT choice is (b) False

For EXPLANATION: Pitot-static system is not a primary measuring instrument. The ALTIMETER, INDICATOR and mach meter are the primary flight instruments. The secondary flight instruments are AIR temperature sensor and ADD’s.

Right option is (B) It is the altimeter reading corrected for instrument error

Explanation: Indicated ALTITUDE is the altimeter reading corrected for instrument error. The indicated altitude will be measured with reference to the APPROPRIATE altimeter datum pressure SETTING.

Correct OPTION is (a) It is the reading of individual mechanical INSTRUMENT which calculates the pressure

Explanation: Altimeter reading is the reading of individual mechanical instrument which calculates the pressure. During these calculations some CORRECTIONS are made to avoid ERRORS that are CAUSED due to mechanical tolerance.