What happens if a string is multiplird by 0(zero)?

Answer 1

Just mention the language you are talking about. It would be easier for others to understand your question.
If you are talking about Python, then you won't get any output as
str = "Hello"
print(0*str) #outputs nothing
So you won't get any output as the there is no string to print

Answer 2

There will be 'No output'

Answer 3

Strictly spoken, in Python, if you multiply any str by 0, you get a str of zero length.