radioaktiivisella

Radioaktiivisella is a Finnish grammatical form rather than a standalone concept. It is the adessive singular form of the adjective radioaktiivinen, which means radioactive. The form is used when describing something in a context that expresses location, presence, or association with radioactivity, typically in combination with a noun in the adessive case.

In Finnish, adjectives agree with the noun in number and case. Therefore radioaktiivinen becomes radioaktiivisella when the noun it modifies is singular and in the adessive case. For example, radioaktiivisella aineella means “with radioactive material,” radioaktiivisella pinnalla means “on a radioactive surface,” and radioaktiivisella säteilyllä can mean “with radioactive radiation.” In plural contexts, the corresponding form is radioaktiivisilla (for adessive plural), as in radioaktiivisilla aineilla.

Radioaktiivisella serves as a descriptor rather than a stand-alone noun. The underlying noun form for the concept is radioaktiivisuus, which translates to radioactivity, while radioaktiivinen serves as the basic adjective. The adessive form is common in technical, scientific, and safety-related Finnish, where precise reference to the presence or association of radioactivity is needed without asserting a specific degree of activity.

See also: radioaktiivisuus, radioaktiivinen, ionisoiva säteily. In context, radioaktiivisella signals that the subject under discussion is related to or characterized by radioactivity, and it requires a noun to complete the meaning.