What are the differences between natural and artificial radioactivity?

Q:What is the difference between natural and artificial radioactivity?

Ans: There is the following difference between Natural and Artificial radioactivity:

NATURAL RADIOACTIVITY	*ARTIFICIAL RADIOACTIVITY*
The spontaneous emission of radiations from an unstable nuclei is known as natural radioactivity.	*The process of emission of radiations from naturally occurring isotopes when they are bombarded with sub-atomic particles or high levels of X-rays or gamma rays.*

More on Natural radioactivity:

Natural radioactivity usually occurs in elements with atomic number greater than 82 which are naturally unstable.
The most of elements which undergo natural radioactivity usually have long half life.
Example:

₉₂²³⁵U à ₉₀²³¹Th + ₂⁴He

More on Artificial radioactivity:

Artificial radioactivity can be induced even in elements with low atomic numbers.
Artificial radioactive elements usually have short half-life.
Example:

Bombardment of Nitrogen gas with alpha particles gives out Oxygen-17 isotope and a Protium.

₇¹⁴N + ₂⁴He à [ ₉¹⁸F] à ₈¹⁷O + ₁¹H