The isotope 239 pu 94 has a half life of 24,400 years. if a sample of nuclear waste originally contained 12kg of 239 pu 94, how much time must pass before the amount falls to 3 kg?

Equation for half-lives:

Nt = No x (1/2)^n

No = initial amount
Nt = final amount after t years
n = number of half lives = t/(single half-life)
t = years

Nt = 3/12 = 0.25
No = 12/12 = 1.00
n = t/(24400)

3/12 = (12/12) x (0.5)^(t/24400)
(0.25) = 1.00 x (0.5)^(t/24400)
0.25/1.00 = 0.5^(t/24400)
ln(0.25) = ln(0.5^(t/24400))
ln(0.25) = (t/24400)*ln(0.5)
ln(0.25)/ln(0.5) = (t/24400)
2 = t/24400
2*24400 = t
t = 48800 yrs

answer is t = 48,800 yrs

Acovalent bond is formed between the two hydrogen bonds

Firstly, the water in the dams hold gravitational potential energy as they are above ground level. the gravitational potential energy is then transferred to kinetic energy as it falls, spinning the turbinethe turbine then spins the generator, which is a large magnet surrounded by metal coils. by doing this, the generator generates electricity. in this action, the energy transfer taken place is kinetic to electric energy