Using charles law
v1/t1=v2/t2
v1=49ml
v2=74
t1=7+273=280k
t2=?
49/280=74/t2
0.175=74/t2 cross multiply
0.175t2=74
t2=74/0.175
t2=422k or 149celcius
Half-life<span> <span>(abbreviated </span>t</span>1⁄2<span>) is the time required for a quantity to reduce to
half its initial value. The term is commonly used in </span>nuclear
physics<span> <span>to describe how quickly
unstable atoms undergo, or how long stable atoms survive, </span></span>radioactive
decay<span>. since it reduce to half after 4000 years, so the
half life is 4000 years</span>
Answer: There are two elements actually and those elements are Carbon and Silicon
Explanation:Plz mark brainliest if im right