[Constructed into adjectives ... -ical and ... Generally speaking, -ic adjectives emphasize their own meanings (historical, classic and classic), while -IC adjectives are mostly extended meanings (historical, classic and first-class).
But there will be exceptions. For example, electricity refers to any device that is charged or generates electricity, and the decorated object itself can also be charged.
Electricity refers to something related to electricity, and the modifier itself can be uncharged (with extended meaning).
Second, the usage is different.
Nouns ending in -ic are all in the form of -IC suffix when they become adjectives.
For example: skeptic .. skeptic. Doubtful, heretical, logicaladj Hysterical dj. Hysterical but there are exceptions, such as public is both a noun and an adjective; Panic (n. Panic), its adjective form is panic.
Third, the parts of speech are different.
Some nouns can only be converted into adjectives with -ic suffix.
For example: drama, drama art drama, drama organ, organ organ.