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Assertion The upper surface of the Wings of an aeroplane is made convex and the Lower surface is made concave. Reason (R) : The air currents at the top have A  smaller and thus less pressure at the Bottom than at the top.

A)  Both A and R are true and R is the correct explanation of A.

B)  Both A and R are true and R is NOT a correct explanation of A.

C)  A is true but R is false.

D)  A is false but R is true.

Correct Answer: C

Solution :

Working of an aeroplane is based on Bernoulli's principle. The wings of the aeroplane are of the shape as shown in figure. Due to this specific shape of wings when the aeroplane runs, air passes at higher speed over it as compared to its lower surface. This difference of air speeds above and below the wings, in accordance with Bernoulli's  principle,  creates  a pressure difference, due to which an upward force called 'dynamic lift' acts on the plane.