Answer:
The radioactive element will be left at 2 p.m. will be 0.25 g.
Explanation:
Half life of the radioactive element =[tex]t_{\frac{1}{2}}=1 hour[/tex]
Initial concentration of the radioactive element = [tex]N_o[/tex]=1.0 g
Time elapsed = 12:00 pm to 2:00 pm = 2 hours
Concentration of radioactive element left = N
[tex]\lambda =\frac{0.693}{t_{\frac{1}{2}}}=\frac{0.693}{1 hr}=0.693 hr^{-1}[/tex]
[tex]\log N=\log N_o-\frac{\lambda t}{2.303}[/tex]
Putting the given values in the above equation we get:
N = 0.25 gram
The radioactive element will be left at 2 p.m. will be 0.25 g.
