Big O notation Log Base 2 or Log Base 10

When articles/question state that the Big O running time of the algorithm is O(LogN) .

For example Quicksort has a Big O running time of O (LogN) where the it is Log base 10 but Height of binary tree is O(LogN+1) where it is Log base 2

Question

1)I am confused over whether is it Log base 10 or Log base 2 as different articles use different bases for their Logarithm .

2) Does it make a difference if its Log base 2 or Log base 10??

3)Can we assume it mean Log base 10 when we see O(LogN)???