A transformer has 100 turns in primary and 200 turns in secondary. If primary voltage is 120 V, the secondary voltage is: MCQ with Answer and Explanation

Explanation:
Angular momentum L = r × p. Position r has [L], linear momentum p = mv has [MLT⁻¹], so L has [L][MLT⁻¹] = [ML²T⁻¹]. This matches Planck's constant dimensions. Option A is linear momentum; C is energy/torque; D is dimensionless. Memory aid: 'Angular momentum: [ML²T⁻¹]; same as action quantities'. This dimensional analysis question tests ability to derive formulas, crucial for competitive exams. Always break down compound quantities into fundamental dimensions (M, L, T) for verification and problem-solving.

Explanation:
Frequency → pitch perception: higher frequency = higher pitch. Loudness depends on amplitude; timbre on waveform; speed on medium properties. Memory aid: 'Frequency = pitch; Amplitude = loudness'. Basic sound property question frequently tested to verify perceptual attribute associations in competitive exams.

Explanation:
Equal masses elastic collision: velocities swap. Moving mass stops, stationary moves with 4 m/s.