Which scientist is associated with the theory of relativity? MCQ with Answer and Explanation

Explanation:
Work done W = charge (Q) × potential difference (V). Thus W = 2 C × 12 V = 24 J. This follows from definition of voltage: 1 volt = 1 joule per coulomb. The work done equals the change in electrical potential energy. This fundamental relationship is crucial in electricity. Memory tip: W = QV is analogous to mechanical work = force × distance. Such direct formula applications are common in competitive exams to test basic concept retention. Always verify units: coulomb × volt = joule, confirming dimensional consistency.

Explanation:
Standard in India: 230 V, 50 Hz (often 220-240).

Explanation:
Work done = F·s = Fs cosθ. Coolie applies vertical force to support weight, displacement horizontal, angle 90°, cos90°=0, work zero. No displacement of force direction. Pushing wall: displacement zero, also zero work. But option A is standard example. Pushing wall also zero, but question expects one answer. I'll adjust: I'll remove 'pushing a wall' to avoid ambiguity. I'll replace with 'A satellite revolving around Earth in circular orbit' etc. However, here I'll keep A, note that pushing wall also has zero displacement, but the question lists specific cases, only one may be correct. Actually, in pushing wall, wall doesn't move, work zero, but often they consider pushing wall as no work. However, option D 'Pushing a wall' might also be zero. To avoid two correct, I'll change D to 'Throwing a ball upward' so only A is zero. I'll modify the question: D: 'Throwing a ball upward' (work positive). So answer A. Let's do that.