The output of `OR` gate is `1`

Options

A. If both inputs are zero
B. If either or both inputs are `1`
C. Only if both inputs are `1`
D. If either input is zero

Answer

B

Explanation

`OR` gate has two inputs `A` and `B` and a output `Y`. It follows `a` logic operation represented by `'+'`. Thus, its Boolean expression is
`A+B=Y`
The truth table of `OR` gate is
`|(A,B,Y),(0,0,0),(0,1,1),(1,0,1),(1,1,1)|`
Thus, after observing its Boolean expression and its truth table, it is obvious that output of `OR` gate is `1` if either or both inputs are `1`.
Aliter: The output of `OR` gate is `Y=A+B`.