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.

Correct answer:

t =  60.5 min

Step-by-step explanation:

$$\begin{gathered} 32\cdot 0.5^{242\mathrm{/}t}=2 \\ 16=2^{242\mathrm{/}t} \\ \ln 16=242\mathrm{/}t\cdot \ln 2 \\ \ln 16\mathrm{/}\ln 2=242\mathrm{/}t \\ t=60.5\text{ min} \end{gathered}$$

Try another example

Related math problems and questions:

• The half life
  The half-life of a radioactive isotope is the time it takes for a quantity of the isotope to be reduced to half its initial mass. Starting with 145 grams of a radioactive isotope, how much will be left after 3 half-lives?
• Crystal
  The crystal grows every month 1.2 permille of its mass. For how many months to grow a crystal from weight 177 g to 384 g?
• Geometric progression
  In geometric progression, a1 = 7, q = 5. Find the condition for n to sum first n members is sn≤217.
• 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?
• Two geometric progressions
  Insert several numbers between numbers 6 and 384 so that they form with the given GP numbers and that the following applies: a) the sum of all numbers is 510 And for another GP to apply: b) the sum of entered numbers is -132 (These are two different geome
• Insert into GP
  Between numbers 5 and 640, insert as many numbers to form geometric progression so the sum of the numbers you entered will be 630. How many numbers must you insert?
• Exponential warm
  Suppose that a body with temperature T1 is placed in surroundings with temperature T0 different from that of T1. The body will either cool or warm to temperature T(t) after time t, in minutes, where T(t)=T0 + (T1-T0)e^(-kt) . If jello salad with 30 degree
• Suppose 2
  Suppose that the half-life of a substance is 250 years. If there were initially 100 g of the substance, a. Give an exponential model for the situation b. How much will remain after 500 years?
• The raw
  The raw data presented here are the scores (out of 100 marks) of a market survey regarding the acceptability of new product launched by a company for a random sample of 50 respondents: 40 45 41 45 45 30 30 8 48 25 26 9 23 24 26 29 8 40 41 42 39 35 18 25 3
• Population
  The town has 65,000 inhabitants. 40 years ago, there were 157,000. How many people will live in a city in 10 years if the population's average rate is as in previous years?
• To the cinema
  Jane at 8 am got message that all 1093 school pupils will go to the cinema. Within 20 min she said it to the three friends. Each of them again for 20 minutes said to the other three. In this way the message spread further. At what time all the children in
• RC time constant
  You introduced 1 Coulomb worth of electrons into the inner volume of a dielectric material with ϵr=6. Thirty minutes later, you found that only 36.79% of the electrons were in the internal volume. Determine the conductivity σ of the dielectric material.
• Sequence
  Calculate what member of the sequence specified by (5^n-2+15) has value 20.
• Exponential equation
  Find x, if 625 ^ x = 5 The equation is exponential because the unknown is in the exponential power of 625
• Geometric sequence
  In the geometric sequence is a₄ = 20 a₉ = -160. Calculate the first member a₁ and quotient q.
• Demographics
  The population grew in the city in 10 years from 30000 to 34000. What is the average annual percentage increase of population?
• Pilsen circus
  The arrival of the circus in Pilsen was seen in the morning at 08:00 by a city citizen. He passed this information on 08:15 to three other residents of the city. Each of these three people then informed the other three residents at 08:30, and again at 08: