**Maximum Value of Voltage in a Sinusoidal AC Cycle**

To determine the maximum value of voltage in a sinusoidal AC cycle, we need to understand the characteristics of a sinusoidal waveform and how it is measured by an ordinary voltmeter.

**Sinusoidal AC Voltage**
A sinusoidal AC voltage is characterized by its frequency and amplitude. The frequency represents the number of complete cycles occurring per second, and it is measured in Hertz (Hz). In this case, the given frequency is 60Hz, which means there are 60 complete cycles in one second.

**Amplitude and Peak Value**
The amplitude of a sinusoidal waveform represents the maximum value it reaches during a cycle. It is commonly denoted as "A" and is measured in volts (V). However, the maximum value of a sinusoidal waveform is often expressed as the peak value instead of the amplitude. The peak value is equal to the amplitude multiplied by the square root of 2 (√2). Mathematically, it can be represented as V_peak = A × √2.

**Voltage Reading by an Ordinary Voltmeter**
An ordinary voltmeter is designed to measure the root mean square (RMS) value of an AC voltage. The RMS value is a measure of the effective voltage and is equal to the DC voltage that would produce the same amount of power in a resistive load. In this case, the voltmeter reads 120V, which represents the RMS value of the sinusoidal AC voltage.

**Calculating the Maximum Value**
To find the maximum value of the sinusoidal AC voltage, we can use the relationship between the RMS value and the peak value. The RMS value is equal to the peak value divided by the square root of 2 (RMS = V_peak / √2).

In this case, the RMS value is given as 120V. Rearranging the formula, we can find the peak value:
V_peak = RMS × √2 = 120V × √2 ≈ 169.71V

Therefore, the maximum value of the voltage in a sinusoidal AC cycle is approximately 169.71V.

**Conclusion**
The maximum value of a sinusoidal AC voltage in a cycle can be calculated using the RMS value obtained from an ordinary voltmeter. By multiplying the RMS value by the square root of 2, we can determine the peak value, which represents the maximum value of the voltage. In this case, the maximum value is approximately 169.71V.

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