Critical Mach number - drag divergence Mach number

Why is fuel stored in the wings of aircraft?

ANSWER:- Fuel is in the wings because it's practical, otherwise cargo and passenger space would be taken up if in the fuselage, but more importantly, the weight of fuel at 7 pounds per gallon has to be stored in a place to keep the aircraft center of gravity centered and balanced as the fuel is burned off. Placing fuel either ahead or behind the center of gravity would be not a safe idea.

Can an Airbus A380 fly upside down?

ANSWER: I am assuming that when you say "fly upside down" you mean sustained inverted flight like an aerobatic airplane. 
The answer is flatly, No. 
Inverted flight requires a specific airfoil (wing shape) as well as specific lubrication systems for the engines. Transport category aircraft are not built to engage in inverted flight.
If, however, your question relates to the ability fly inverted for only a few seconds. Then I believe the answer would be yes. 
Any airworthy aircraft should be able to complete a 1G barrel roll at the hands of a well trained pilot proficient in the maneuver. A properly executed 1G barrel roll will not over-stress the aircraft or affect lubrication in anyway. The danger is that an improperly executed barrel roll can get out of control very quickly.

The master of this maneuver was Bob Hoover who used to execute 1G barrel rolls in a twin-engine aircraft with one engine shut down WHILE pouring a cup of iced tea into a cup which was sitting up on the glareshield (dash) of the aircraft.
The Airbus, being a fly-by-wire aircraft has limitations in place that would prohibit the execution of this maneuver, but with special procedures these limiting system can be disabled.

propulsive efficiency

Q.7 Which of the following aircraft engines has the highest propulsive efficiency at a cruising Mach number of less than 0.5?
(A) Turbofan engine 
(B) Turbojet engine
(C) Turboprop engine
(D) Ramjet engine

Correct Answer:-
(C)
Propulsive efficiency depends on specific thrust,at low Mach Number 0.5 or 0.6, turboprop engine have the superior efficiency compare to other engines.

Airfoil nomencleture

Q. Which of the following airfoil will have location of the maximum camber at half chord length from the leading edge?
(A) NACA 5212 
(B) NACA 1225 
(C) NACA 2215 
(D) NACA 2512

Correct Answer:-
(D)
Let's consider the length of the chord is 100%, then the location of the maximum camber is 50%.According to the NACA 4-series ,2nd position is for the tenth location of maximum camber.

Aerodynamics mcq critical mach number

Q.1 With increase in air-foil thickness, the critical Mach number for an air-foil is likely to
(A) decrease. 
(B) increase. 
(C) remain unchanged. 
(D) be undefined.

Correct Answer:-
(A)

IAS

Indicated airspeed is used by a pilot during
(A) take-off. 
(B) navigation.
(C) setting the engine RPM. 
(D) setting the elevator angle.

Correct Answer:-
(A)