Specific heat capacity of water is 1 cal/g°C. Heat required to raise temperature of 200 g water from 25°C to 35°C is MCQ with Answer and Explanation

Explanation:
Work per minute = mgh = 200×10×15 = 30000 J. Power = 30000/60 = 500 W.

Explanation:
Time for to-and-fro: t = 2d/v ≥ 0.1 s ⇒ d ≥ vt/2 = 340×0.1/2 = 17 m. Minimum distance for brain to distinguish echo from original sound. Memory tip: 'd_min = v×persistence/2'. Application of sound reflection with human perception limit, common in competitive exam numericals.

Explanation:
Refrigerant evaporates inside absorbing heat, compressed outside releasing heat, cycle repeats.