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2 answers:
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Answer : The time passed in years is
Explanation :
Half-life of carbon-14 = 5730 years
First we have to calculate the rate constant, we use the formula :
Now we have to calculate the time passed.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant =
t = time passed by the sample = ?
a = initial amount of the reactant disintegrate = 15.3
a - x = amount left after decay process = 14.8
Now put all the given values in above equation, we get
Therefore, the time passed in years is
The cost of painting the traffic sign of 7.065 square feet is approximately equal to 25 dollar.
<u>Explanation:</u>
The cost of painting the circular traffic sign is given as 3.50 dollar per square feet. The diameter of the traffic sign is 36 inch, then its radius will be inches.
But as the cost is given in unit of feet, we have to convert the radius from inches to feet.
1 inches = 0.0833 feet
18 inches = 18 × 0.0833 feet
So, the radius of the traffic sign will be approximately equal to 1.5 feet.
The area of the traffic sign will be square feet.
So, if the cost of painting 1 square feet of traffic sign is 3.50 dollar, then
cost of painting 7.065 square feet of traffic sign = 3.50 × 7.065 = 24.7 dollar.
Thus, the cost of painting the traffic sign of 7.065 square feet is approximately equal to 25 dollar.