Half-life is defined as the amount of time it takes a given quantity to decrease to half of its initial value. The equation to describe the decay is
Nt=N0(1/2)
where N0 is the initial quantity, Nt is the remaining quantity after time t, t1/2 is the half-time. So work out the equation, t1/2 = t (-ln2)/ln(Nt/N0) = 11.5*(-ln2)/ln(12.5/100) = 3.83 days
Answer:
Explanation:
When adding or subtracting values, you must round your answer to the same "place" as the measurement with its last significant figure furthest to the left.
That is, you round off to the same number of decimal places as the measurement with the fewest decimal places.
The measurements of 14.0 and 10.6 have one digit after the decimal point, so you round the sum to have only one digit to the right of the decimal.
The number to be dropped (3) is less than 5, so you drop it.
Since they can still be unstable...nuetral atoms have the same amount of protons to electrons but to be stable they need to fill up there outer shell by gaining or losing electrons
The pressure of diver = atmospheric pressure + water pressure
atmospheric pressure = 750 mmHg (as given) = 750 / 760 atm = 0.987 atm
Water pressure is
P = hρg
where
h = height of water = 38 ft
1 ft = 0.3048
38 ft = 11.58 m
ρ = density = 1000 Kg / m³
g = gravitational constant = 9.81 m/s2
P = 11.58 X 1000 X 9.81 = 113599.8 Kg / m s^2 Or N /m^2
1 N / m^2 = 1 pa = 9.869 X 10^-6 atm
P = 113599.8 Pa = 1.12 atm
Total pressure = 1.12 + 0.987 atm = 2.107 atm = 2.1 atm (two significant figures)
