A NOR gate can be described as

A NOR gate can be described as

• A. An OR gate followed by a NOT
• B. An AND gate followed by a NOT
• C. A NOT gate
• D. An OR gate

Answer: (A)

A NOR gate computes the inverse of the OR of its inputs. In other words, you first feed the inputs into an OR gate, and then you invert that output. If both inputs are 0, the OR output is 0 and the NOT makes it 1; if either input is 1, the OR output is 1 and the NOT flips it to 0. So the overall behavior is 1 only when both inputs are 0. That matches the description of “an OR gate followed by a NOT.” If you instead paired an AND gate with a NOT, you’d get NAND; using an OR without inversion would be just OR; a single NOT gate wouldn’t handle two inputs.

A NOR gate computes the inverse of the OR of its inputs. In other words, you first feed the inputs into an OR gate, and then you invert that output. If both inputs are 0, the OR output is 0 and the NOT makes it 1; if either input is 1, the OR output is 1 and the NOT flips it to 0. So the overall behavior is 1 only when both inputs are 0. That matches the description of “an OR gate followed by a NOT.” If you instead paired an AND gate with a NOT, you’d get NAND; using an OR without inversion would be just OR; a single NOT gate wouldn’t handle two inputs.