Question

What is a base in binary?

Answer 1

Something like

Answer 2

Not sure what you mean. The base in binary is 2.
The decimal system is based on base 10.

What you drew there looks like it can mean 10 in base 12, which would be equal to 12 in decimal base.

So for base 10, you have digits 0,1,2,3,4,5,6,7,8,9
each digit place is base^place but starting from place = zero
so 10^n.... 10^2...10^1...10^0
923 in base 10 is
9 digit * 10^2 + 2 digit * 10^1 + 3 digit * 10^0

xyz in base b is
x digit * b^2 + y digit * b^1 + z digit * b^0

so 10 in base 12 = 1 * 12^1 + 0 * 12^0 = 12 in base 10
10 in base 2 = 1 * 2^1 + 0 * 2^0 = 2 in base 10