Consider the following Assertion (A) and Reason (R) and choose your answer from given code: Assertion (A) : The upper surface of the wings of an aeroplane is made convex and the lower surface is made concave. Reason (R) : The air current at the top has less velocity and thus less pressure at the bottom than at the top. Code :

Assertion (A) is largely true; aeroplane wings (airfoils) are designed with an asymmetric cross- section where the upper surface is significantly more curved (convex) than the lower surface (often relatively flat or slightly concave). Reason (R) is false. According to Bernoulli's principle, for lift to be generated, the air flowing over the longer upper curved surface must travel faster than the air flowing under the wing. Higher velocity corresponds to lower pressure (and vice-versa). Therefore, the pressure on the top surface is less than the pressure on the bottom surface, creating an upward pressure difference (lift). Reason (R) incorrectly states the opposite relationship between velocity and pressure, and the pressure difference direction.