Define the following terms:
$1.$ Effective collision
$2.$ Probability or steric factor $(P)$

(N/A) $1.$ Effective collision: Collisions between reactant molecules that result in the formation of products are known as effective collisions. For a collision to be effective,the molecules must possess a minimum amount of energy (activation energy) and must be oriented in a favorable direction during the collision.
$2.$ Probability or steric factor $(P)$: The steric factor $(P)$ accounts for the requirement of proper orientation of reactant molecules during a collision. It is defined as the ratio of the experimental rate constant to the rate constant calculated using the collision theory. It is often included in the Arrhenius equation as $k = P \cdot Z_{AB} \cdot e^{-E_a/RT}$.