Physics
A standing wave occurs when

The speed of the wave is zero or near zero
The amplitude of a wave exceeds its wavelength
A wave reflects upon itself
Two waves overlap

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Physics
To prevent damage from lightning, lightning conductors are used on tall structures. The lightning conductor

Should be made of a good conductor but can be of any shape
Can be of any shape
Should be made of a good conductor like copper with sharp-pointed edges
Should be in the form of a vertical rod

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