Board-style MCQs and past-paper numericals in the BIEK / Sindh Board pattern. Tap an option to check yourself instantly. Solved questions are at the bottom.
Multiple-choice questions
Solved numericals (past papers)
Wavelength and period of a tabla note
f = 250 Hz; speed of sound v = 340 m/s.
λ = v/f = 340/250 = 1.36 m
T = 1/f = 1/250 = 4 × 10⁻³ s = 4 ms
Tuning a sitar string by beats
440 Hz fork with the string → 4 beats/s, so string = 444 or 436 Hz.
Tightening (raises f) SLOWS the beats → the string's f moved towards 440 → it was below 440.
original frequency = 436 Hz
Fundamental frequency of a stretched string
L = 0.60 m; m = 1.0 × 10⁻³ kg/m; F = 90 N.
v = √(F/m) = √(90/0.001) = √(9 × 10⁴) = 300 m/s
f₁ = v/2L = 300/(2 × 0.60) = 250 Hz (harmonics: 500, 750, 1000 Hz …)
Speed of sound by the resonance tube
f = 512 Hz; first resonance L₁ = 16.0 cm; second resonance L₂ = 49.5 cm.
λ = 2(L₂ − L₁) = 2(0.495 − 0.160) = 0.670 m (end-correction cancels)
v = fλ = 512 × 0.670 ≈ 343 m/s