1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
gayaneshka [121]
3 years ago
9

Assume you have such a watch. if a minimum of 18.0% of the original tritium is needed to read the dial in dark places, for how m

any years could you read the time at night? assume first-order kinetics.
Mathematics
1 answer:
laila [671]3 years ago
5 0
Given that the half life of 3H is 12.3 years.

The amount of substance left of a radioactive substance with half life of t_{ \frac{1}{2} } after t years is given by

N(t)=N_0\left(\frac{1}{2} \right)^{ \frac{t}{t_{\frac{1}{2}} }

Therefore, the number of years it will take for 18% of the original tritinum to remain is given by

18 \% = 100 \% \left(\frac{1}{2} \right)^{ \frac{t}{12.3}} \\  \\ \Rightarrow\left(\frac{1}{2} \right)^{ \frac{t}{12.3}} =0.18 \\  \\ \Rightarrow\frac{t}{12.3}\ln\left(\frac{1}{2} \right)=\ln0.18 \\  \\ \Rightarrow\frac{t}{12.3}= \frac{\ln0.18}{\ln\left(\frac{1}{2} \right)} = \frac{-1.715}{-0.6931} =2.474\\ \\ \Rightarrow t=2.474(12.3)=30.4

Therefore, the number of <span>years that the time could be read at night is 30.4 years.</span>
You might be interested in
Solve the equation for x. Enter your answers as radical expressions. Then estimate to one decimal place, if necessary.
Darya [45]

Hope you won't be turned off by a correction, but we really need to use the symbol " ^ " to denote exponentiation.

Thus, we have x^2 = 100

Taking the square root of both sides, we get x = plus or minus 10. Verify, please, that both x = -10 and x = +10 satisfy the given equation.

3 0
3 years ago
The answers..............................
HACTEHA [7]

Answer:

DAM BROOOOO UR SCREEN.

Step-by-step explanation:

5 0
2 years ago
Find the first of three consecutive even integers if the sum of the first and second is 15 less than 3 times the third.
lilavasa [31]

Answer:

<em>First even integer: 6</em>

Step-by-step explanation:

<u>Inequalities</u>

Assume x is the first even integer. The next integer is x+2, and the last integer ix x+4.

The condition states that the sum of the first and the second number is 15 less than three times the third. This takes us to the inequality:

x+x+2

Operating:

2x+2

Subtracting 2 and 2x:

0

Simplifying:

0

Solving:

x>5

There are infinitely many solutions. For example, for x=6 (first even number into the solution interval):

First integer: 6

Second integer: 8

Third integer: 10

There are other solutions, like 20,22,24 but the first set is 6,8,10.

4 0
3 years ago
To the nearest tenth, what is the area of the figure shown in the image? Segment BF is a line of symmetry of the pentagon ABCDE.
Sidana [21]

Answer:

C, 39.3 in²

Step-by-step explanation:

Lets first find the area of the rectangle part of the house.

To find the area of a rectangle its base × height.

So its 6×4=24 in².

Now lets find the area of the top triangle.

Area for a triangle is (base × height)/2.

The height is 3 inches, because its 7-4. While the base is 6 inches.

(6×3)/2=9 in².

To find the area of the half circle the formula, (piR²)/2.

The radius of the circle is 2 because its half of the diamter which is 4.

(pi2²)/2=6.283 in².

Now we just need to add up the area of every part,

24+9+6.283=39.283in²

5 0
3 years ago
What percent of 100 is 5?
Murrr4er [49]
5 is the answer. 100% of any number is that number
6 0
3 years ago
Other questions:
  • How many yards a football team moves on a field using this expression |8| + |-4|
    12·1 answer
  • Why is there no set path that I've scientific inquiry must follow
    13·2 answers
  • Can I ge some help on this please
    11·2 answers
  • A = 1/2ha +1/2hb solve for b
    15·1 answer
  • WILL GIVE BRAINLIEST AND 20 POINTS!
    8·2 answers
  • Please help me and I’ll give you brainiest!!!!!!!!!
    8·1 answer
  • Becky has 4 1/2 cups of ice cream. If each ice cream scoop is 1/2 cup, how many scoops of ice cream can she make?
    9·2 answers
  • What is the slope of the line.
    5·2 answers
  • ***<br> Write the rule for the value of the term of the geometric sequence:<br> -5, 10, 20, 40, ..
    14·1 answer
  • Make and equation using the numbers 1, 7, 2, and 2. You can merge the numbers like turning 1 and 7 to 17 in your equation. It ha
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!