A transformer steps up 220 V to 2200 V. The turn ratio (secondary to primary) is MCQ with Answer and Explanation

Explanation:
Apparent loss in weight = buoyant force = weight in air - weight in water = 5 N. Archimedes principle. Apparent weight = 20-5 = 15 N.

Explanation:
Wave speed v = frequency (f) × wavelength (λ). Thus v = 50 Hz × 2 m = 100 m/s. This fundamental wave equation applies to all periodic waves (sound, light, water). Memory aid: 'v = fλ – the universal wave equation'. Competitive exams frequently test this direct calculation. Always ensure units: Hz = s⁻¹, so (s⁻¹)×m = m/s, correct for speed. This problem assesses basic wave property understanding, crucial for sound and light topics.

Explanation:
Work done is given by W = F * d * cos(theta). In uniform circular motion, the centripetal force is always directed strictly towards the center of the circle, while the instantaneous displacement (velocity vector) is tangential to the circle. The angle (theta) between them is exactly 90 degrees. Since cos(90) = 0, the work done by the centripetal force is always zero.