The half-life of Strontium-90 is 28.8 years. how long will it take for 3/4 of a sample of Strontium-90 to decay? (you can include work but u don’t have to)

Ageochemist examines a piece of metal that he found in the soil. he performs tests to identify the metal from its density, electrical conductivity, and melting point. which statement best describes his investigation? a. he is determining physical properties that are sufficient to identify the metal.b. he is determining chemical properties that are sufficient to identify the metal.c. he is determining physical properties that are insufficient to identify the metal.d. he is determining chemical properties that are insufficient to identify the metal.