Answer:
Explanation:
Given
N0 = 20kg (original substance)
decay constant λ = 0.179/sec
time t = 300s
We are to find N(t)
Using the formula;
n(t) = N0e^-λt
Substitute the given values
N(t) = 20e^-(0.179)(300)
N(t) = 20e^(-53.7)
N(t) = 20(4.7885)
N(t) =143.055
To know how much of the original material that is active, we will find N(t)/N0 = 143.055/20 = 7.152
About 7 times the original material is still radioactive
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Answer:
a. It became deeper by a factor of 3.
Explanation:
What we have is water flowing down a river with constant width. The water slows from speed v to v3 over a shirt distance
Using the equation of continuity
A1V1 = A2V2 ----1
A1 is the area of rectangle
V1 is the velocity of water
Area of rectangle = length x width
We rewrite equation 1 as
λ1w1v1 = λ2w2v2
We have w1 = w2
λ1v1 = λ2v2
λ1*v1 = λ2*v/3
λ1 = λ2/3
So it becomes deeper by a factor of 3
The answer is D.
C and A are incomplete as they only treat specific types of energy, and B doesn't answer the question.
Answer:
6.34×10⁹ seconds
Explanation:
Applying,
V = d/t............. Equation 1
Where V = speed plate, d = distance covered by the plate, t = time it takes the plate to travel
make t the subject of the equation
t = d/V............ Equation 2
From the question,
Given: d = 5 cm/yr = (5×3.154×10⁻⁹) = 1.577×10⁻⁸ m/s, d = 100 meter
Substitute these values into equation 2
t = 100/1.577×10⁻⁸
t = 6.34×10⁹ seconds
Hence the time it takes the the plate to travel is 6.34×10⁹ seconds