Which physical law explains the generation of lift force on an airplane wing?
A. Bernoulli's Principle
B. Archimedes' Principle
C. Boyle's Law
D. Pascal's Law
Answer: Option A
Solution (By JKSSB Mock Tests)
Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure. Airplane wings (airfoils) are shaped so that air travels faster over the curved top surface than the flat bottom. This creates lower pressure above the wing and higher pressure below, resulting in an upward lift force.
Explanation:
Work done to charge a capacitor is stored as electrostatic potential energy in the electric field between plates: U = ½QV = ½CV² = Q²/(2C). This energy can be recovered when capacitor discharges. Heat (A) is dissipated in resistance during charging, but ideal capacitor stores energy electrostatically. Memory aid: 'Capacitor energy = ½CV², stored in electric field'. This electrostatics concept is frequently tested in competitive exams. Always distinguish ideal capacitor (no resistance) from real circuits where some energy is lost as heat during charging.
A ray of light traveling from water (denser) into air (rarer) grazes the interface separating the two media. The angle of incidence in the water is called the:
Explanation:
When light travels from an optically denser medium to a rarer medium, it bends away from the normal. As the angle of incidence increases, the angle of refraction also increases. The specific angle of incidence for which the refracted ray grazes the surface (meaning the angle of refraction is exactly 90 degrees) is defined as the critical angle.
No comments yet. Be the first to start the discussion!