Final answer:
The necessity for a larger filter inductor in bridge inverters with bipolar modulation as compared to unipolar modulation is false, as unipolar modulation may require a larger inductor. It is also false that high-voltage power lines are insulated; they are typically bare. Lastly, waves with different frequencies can indeed superimpose upon each other, and this is true.
Step-by-step explanation:
The statement about bridge inverter modulation techniques impacting the size of the filter inductor is false. In the context of power electronics, particularly in inverters, bipolar modulation switches the output voltage between the positive and negative values of the DC supply voltage, while unipolar modulation switches between the positive DC voltage and zero, or between the negative DC voltage and zero.
Bipolar modulation tends to result in higher harmonic content in the output waveform than unipolar modulation. However, unipolar modulation, which can switch more frequently, may require larger filtering components to smooth out the output waveform due to its higher switching frequency. Thus, a bridge inverter with unipolar modulation would typically require a larger filter inductor than one with bipolar modulation.
As for high-voltage wires, the statement is false. The high-voltage power lines you see on metal-frame towers are not covered in insulating material. They are held aloft by insulating connectors, but are typically bare wires because the air acts as an insulator and it's both impractical and unnecessary to insulate them in an open-air environment.
Regarding waves, the statement that they can superimpose even if their frequencies are different is true. This phenomenon is known as the principle of superposition, which applies to waves in physics. When two or more waves encounter each other, they superimpose to form a new wave pattern, this can happen regardless of their frequencies.