Half life

Determine the half life of bismuth, when bismuth weight from the original weight of 32 g was only 2 grams in 242 minutes.

Result

t =  60.5 min

Solution:

32⋅0.5242/t=2 16=2242/t ln⁡16=242/t⋅ln⁡2 ln⁡16/ln⁡2=242/t t=60.5 min32 \cdot 0.5^{242/t} = 2 \ \\ 16 = 2^{242/t} \ \\ \ln 16 = 242/t \cdot \ln2 \ \\ \ln 16 / \ln 2 = 242/t \ \\ t = 60.5 \ \text{min}

Try another example


Our examples were largely sent or created by pupils and students themselves. Therefore, we would be pleased if you could send us any errors you found, spelling mistakes, or rephasing the example. Thank you!





Leave us a comment of this math problem and its solution (i.e. if it is still somewhat unclear...):

Showing 0 comments:
1st comment
Be the first to comment!
avatar




Tips to related online calculators
Do you have a linear equation or system of equations and looking for its solution? Or do you have quadratic equation?
Do you want to convert time units like minutes to seconds?

You need to know the following knowledge to solve this word math problem:

Next similar math problems:

  1. Radioactivity
    radioactivity After 548 hours decreases the activity of a radioactive substance to 1/9 of the initial value. What is the half-life of the substance?
  2. Logarithm
    log_hat Determine the number whose decimal logarithm is -3.8.
  3. Theorem prove
    thales_1 We want to prove the sentence: If the natural number n is divisible by six, then n is divisible by three. From what assumption we started?
  4. Demographics
    population The population grew in the city in 10 years from 42000 to 54500. What is the average annual percentage increase of population?
  5. Insert into GP
    archimedes_1 Between numbers 5 and 640 insert as many numbers to form geometric progression so sum of the numbers you entered will be 630. How many numbers you must insert?
  6. Population
    population_2 What is the population of the city with 3% annual growth, if in 10 years the city will have 60,000 residents?
  7. The city 3
    city_2 The city has 22,000 residents. How long it is expected to have 25,000 residents if the average annual population growth is 1.4%?
  8. Six terms
    sequence_geo_3 Find the first six terms of the sequence a1 = -3, an = 2 * an-1
  9. Sequence
    seq Calculate what member of the sequence specified by ? has value 86.
  10. Intercept with axis
    log_10 F(x)=log(x+4)-2, what is the x intercept
  11. Geometric progression 2
    exp_x There is geometric sequence with a1=5.7 and quotient q=-2.5. Calculate a17.
  12. Exponential equation
    exp In the set R solve the equation: ?
  13. Log
    log if ?, what is b?
  14. Five harvests
    zrno In the seed company, they know that, out of 100 grains of a new variety, they get an average of 2000 grains after harvest. Approximately how many grains do they get out of 100 grains after five harvests?
  15. Population
    population_1 The town has 65,000 inhabitants. 40 years ago there were 157,000. How many people will live in town in 10 years if the average rate in population is as in previous years?
  16. Water lilies
    lekno_2 Water lilies are growing on the pond and their number is doubled every day. The whole layer is covered in 12 days. How many days will it cover 8 layers?
  17. Powers 3
    exp_4 2 to the power of n divided by 4 to the power of -3 equal 4. What is the vaule of n?