Hydraulic brakes used in automobiles operate on the basis of: MCQ with Answer and Explanation

Explanation:
Beats: interference of close frequencies (Δf small, typically

Explanation:
Fundamental units: kg, m, s, A, K, mol, cd. Newton is derived (kg m/s²). Therefore, Newton is not fundamental. Remember the seven base units.

Explanation:
Energy stored in capacitor U = ½CV² = ½QV = Q²/(2C). This derives from work done to charge the capacitor against increasing voltage. Option A has wrong dimensions (energy should be joules, CV is coulomb-volt = joule, but missing factor ½); C and D are dimensionally incorrect. Memory tip: 'Capacitor energy = ½CV², analogous to spring energy ½kx²'. This formula-based question tests electrostatics knowledge, frequently appearing in competitive exams. Always recall the three equivalent forms and choose based on given quantities.