Question

Observation that a bubbled input or gate is interchangeable with a bubbled output and gate is referred to as:

Answer 1

 

The observation that a bubbled input OR gate is interchangeable with a bubbled output AND gate is referred to as De Morgan 's second theorem

Answer 2

Answer:

The observation is referred to as DE Morgan’s second theorem

DE Morgan’s theorem is used to find the solution to the problems related to Boolean algebras

It refers to the NOR gate which is similar to the bubbled AND  

Here when both inputs A and B are 0 then the output is true, if the inputs A and B are 0 and 1 or 1 and 0 then the output is false, if the inputs are 1 and 1 then the resultant output is false that is

A B OUTPUT

0 0     1

0 1     0

1 0    0

1 1     0