What is the output of a NOR gate when any input is high (1)?

A NOR gate is a digital logic gate that outputs true or high (1) only when all its inputs are false or low (0). In other words, a NOR gate serves as an inversion of an OR gate. If any one of its inputs is high (1), the output will necessarily be low (0).

Thus, when considering the condition specified in the question—where at least one input is high—the NOR gate's behavior dictates that it can only produce a low output. Since the NOR gate rejects any presence of a high signal, this confirms that the output will indeed be 0 when any input is high. This principle is fundamental in digital electronics design and understanding how logic gates function in circuits.