The number of strictly increasing functions \(f\) from the set \(\{1, 2, 3, 4, 5, 6\}\) to the set \(\{1, 2, 3, ...., 9\}\) such that \(f(i)>i\) for \(1 \le i \le 6\), is equal to:
If a random variable \( x \) has the probability distribution 
then \( P(3<x \leq 6) \) is equal to
An infinitely long straight wire carrying current $I$ is bent in a planar shape as shown in the diagram. The radius of the circular part is $r$. The magnetic field at the centre $O$ of the circular loop is :

Permutation is the method or the act of arranging members of a set into an order or a sequence.
Combination is the method of forming subsets by selecting data from a larger set in a way that the selection order does not matter.