If the half-life of a radionulide is 1 month, what percent remains after 4 months?

6.25% of the original amount

Explanation:

half-life means that half is gone for every certain period of time. Because the half life is 1 month, only half of the 'radionulide' is left every month.

after 1 month= 50%

after 2 months= 25%

after 3 months= 12.5%

after 4 months= 6.25%

plasma is the state of matter where the substance is ionized and has no definite shape or volume. the fact of being ionized makes the substance a good electrical conductor.