Answer: t-half = ln(2) / λ ≈ 0.693 / λExplanation:The question is incomplete, so I did some research and found the complete question in internet.
The complete question is:
Suppose a radioactive sample initially contains
N0unstable nuclei. These nuclei will decay into stable
nuclei, and as they do, the number of unstable nuclei that remain,
N(t), will decrease with time. Although there is
no way for us to predict exactly when any one nucleus will decay,
we can write down an expression for the total number of unstable
nuclei that remain after a time t:
N(t)=No e−λt,
where λ is known as the decay constant. Note
that at t=0, N(t)=No, the
original number of unstable nuclei. N(t)
decreases exponentially with time, and as t approaches
infinity, the number of unstable nuclei that remain approaches
zero.
Part (A) Since at t=0,
N(t)=No, and at t=∞,
N(t)=0, there must be some time between zero and
infinity at which exactly half of the original number of nuclei
remain. Find an expression for this time, t half.
Express your answer in terms of N0 and/or
λ.
Answer:
1) Equation given:
← I used α instead of λ just for editing facility..
Where No is the initial number of nuclei.
2) Half of the initial number of nuclei:
N (t-half) = No / 2So, replace in the given equation:
3) Solving for α (remember α is λ)
αt ≈ 0.693
⇒ t = ln (2) / α ≈ 0.693 / α ← final answer when you change α for λ
Answer: -9
Step-by-step explanation: it is a negative because it is minus 9$ from the price just like adding -9
The answer is 10 because it all goes up by 10
Answer: 14 red, 7 green, 44 blue
Step-by-step explanation:
First, use the letter <em>r</em> as a variable to represent the number of red Legos. The number of green Legos (<em>g</em>) is 7 less than the number of red Legos, or <em>g = r-7.</em> The number of blue Legos (b) is 2 more than 3 times the number of red Legos, or <em>b = 3r+2</em>. The total number of Legos is the number of red + green + blue Legos, which can be represented as <em>65 = r+g+b</em>.
Substitute the equations for g and b in. This should give you a final equation of <em>65 = r+(r-7)+(3r+2)</em>. To solve for the number of <u>red</u> Legos, first add up all of the terms to get <em>65 = 5r-5</em>. Now add 5 to each side (70<em> = 5r</em>). Finally, divide each side by 5 (r = 14).
To find the number of <u>green</u> Legos, substitute the number of red Legos (14) into the equation for the green Legos (<em>g = r-7</em>). This should get you the equation <em>g = 14-7</em> which simplifies to g = 7.
To find the number of <u>blue</u> Legos, substitute the number of red Legos (14) into the equation for the blue Legos (<em>b = 3r+2</em>). This gives you the equation <em>b = (3*14)+2.</em> First, multiply 3 and 14 to get <em>b = 42+2</em>. Finally, add them together to get b = 44.