The standard equation describing a sound wave is \( y = A \cos(kx - \omega t) \), where \( A \) represents the amplitude, \( k \) denotes the wave number, and \( \omega \) signifies the angular frequency. The velocity of the wave, \( v \), is determined by the equation: \[ v = \frac{\omega}{k}. \] Accordingly, the correct selection is option (1).
Two resistances of 100Ω and 200Ω are connected in series with a battery of 4V and negligible internal resistance. A voltmeter is used to measure voltage across the 100Ω resistance, which gives a reading of 1V. The resistance of the voltmeter must be _____ Ω.