Aim: To determine the frequency of alternating current (AC mains, 50 Hz) using a sonometer, step-down transformer, and permanent horseshoe magnet / electromagnet.
Measure the frequency of AC mains using a sonometer and electromagnet. When the wire’s natural frequency matches 50 Hz, transverse standing wave resonance throws the paper rider off the antinode!
Relation: T / l² = 4m·f² = constant ⟹ f = ½ · √((T/l²) / m)
| Obs # | Mass M (kg) | Tension T = Mg (N) | Bridge A (cm) | Bridge B (cm) | Length l (cm) | Length l (m) | l² (m²) | T / l² (N/m²) | Calculated f (Hz) |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 1 | 9.8 | 10 | 89.2 | 79.2 | 0.792 | 0.627 | 15.63 | 50 |