Half-life of a radioactive substance is the time required to reduce the amount of substance to half of its initial amount.
In present case, half-life is material is given as 1000 years and initial amount of material is given as 400 kg
Answer 1) Since, half-life of radio-active substance is 1000 years, therefore after 1st half life, amount of the material will be left to half the initial amount. Hence, amount of substance left after 1000 years = 400/2 = 200 kg.
Answer 2) For 2000 years, radioactive material has crossed 2 times the half life. Therefore , amount of the material will be left to 1/4 the initial amount. Hence, amount of substance left after 2000 years = 400/4 = 100 kg.
Answer 3) For 4000 years, radioactive material has crossed 4 times the half life. Therefore , amount of the material will be left to 1/16 the initial amount. Hence, amount of substance left after 4000 years = 400/16 = 25 kg.
You can put an egg in Vinegar an egg in Olive oil
Answer:
1. Hydrogen
Explanation:
These planets contain liquid hydrogen in their interior, while the earth has liquid iron in it.
When liquid hydrogen is in tremendous pressure enviroments, the electrons that make up each atom of this element end up "jumping" to other atoms. These "jumps" allow liquid hydrogen to behave like a metal.
In addition, with the constant energy released by the nucleus of planets like Jupiter and Saturn, as well as their rotations, the liquid hydrogen receives induction of currents, giving rise to extremely powerful magnetic fields.
