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
tekilochka [14]
3 years ago
13

A freshly prepared sample of radioactive isotope has an activity of 10 mCi. After 4 hours, its activity is 8 mCi. Find: (a) the

decay constant  and half-life T1/2; (b) How many atoms of the isotope were contained in the freshly prepared sample? (c) What is the sample's activity 30 hours after it is prepared?
Physics
1 answer:
Maurinko [17]3 years ago
4 0

Answer:

(a). The decay constant is 1.55\times10^{-5}\ s^{-1}

The half life is 11.3 hr.

(b). The value of N₀ is 2.38\times10^{11}\ nuclei

(c). The sample's activity is 1.87 mCi.

Explanation:

Given that,

Activity R_{0}=10\ mCi

Time t_{1}=4\ hours

Activity R= 8 mCi

(a). We need to calculate the decay constant

Using formula of activity

R=R_{0}e^{-\lambda t}

\lambda=\dfrac{1}{t}ln(\dfrac{R_{0}}{R})

Put the value into the formula

\lambda=\dfrac{1}{4\times3600}ln(\dfrac{10}{8})

\lambda=0.0000154\ s^{-1}

\lambda=1.55\times10^{-5}\ s^{-1}

We need to calculate the half life

Using formula of half life

T_{\dfrac{1}{2}}=\dfrac{ln(2)}{\lambda}

Put the value into the formula

T_{\dfrac{1}{2}}=\dfrac{ln(2)}{1.55\times10^{-5}}

T_{\dfrac{1}{2}}=44.719\times10^{3}\ s

T_{\dfrac{1}{2}}=11.3\ hr

(b). We need to calculate the value of N₀

Using formula of N_{0}

N_{0}=\dfrac{3.70\times10^{6}}{\lambda}

Put the value into the formula

N_{0}=\dfrac{3.70\times10^{6}}{1.55\times10^{-5}}

N_{0}=2.38\times10^{11}\ nuclei

(c). We need to calculate the sample's activity

Using formula of activity

R=R_{0}e^{-\lambda\times t}

Put the value intyo the formula

R=10e^{-(1.55\times10^{-5}\times30\times3600)}

R=1.87\ mCi

Hence, (a). The decay constant is 1.55\times10^{-5}\ s^{-1}

The half life is 11.3 hr.

(b). The value of N₀ is 2.38\times10^{11}\ nuclei

(c). The sample's activity is 1.87 mCi.

You might be interested in
Suppose that you measure the length of a spaceship, at rest relative to you, to be 400 m. how long will you measure it to be if
Fantom [35]

Calculate the length of a spaceship as follows:

l = l₀√1 - v²/c²

=(400 m)√1 - (0.75c)2 c²

=264.575m.

The Spaceship Origin Portfolio is an index fund that invests in listed Australian and global equities by market capitalization. Invest in the top 100 Australian and top 100 international companies.

Starships, also known as star cruisers, starships, spacecraft, or simply starships or ships, were vessels designed specifically for interstellar travel between star systems.

For clients in the Spaceship Index portfolio, the situation is a little different. The Spaceship Index portfolio consists of approximately 100 of his ASX-listed companies with the largest market capitalization and approximately 100 global companies with the largest market capitalization.

Learn more about spaceship at

brainly.com/question/28175986

#SPJ4

8 0
1 year ago
Explain why greenhouse gases in the atmosphere cause an increase in temperature?
harkovskaia [24]
Any gas in the atmosphere that absorbs and emits thermal infrared radiation is referred to as a greenhouse gas (GHG). These are the primary causes of the greenhouse effect, which causes the Earth's temperature to rise. Earth is warmer because less heat radiates into space.
6 0
2 years ago
Which of the following statements about energy in systems is true?
Elena-2011 [213]
Option number three is correct energy can be transformed and moved and released but it can't be destroyed and doesn't disappear.
8 0
3 years ago
A basketball is tossed up into the air, falls freely, and bounces from the wooden floor. From the moment after the player releas
Tju [1.3M]

Answer:

Tha ball- earth/floor system.

Explanation:

The force acting on the ball is the force of gravity when ignoring air resistance. At the moment the player releases the ball, until it reaches the top of its bounce, the small system for which the momentum is conserved is the ball- floor system. The balls exerts and equal and opposite force on the floor. <u>Here the ball hits the floor, because in any collision the momentum is conserved. Moment of the ball -floor system is conserved</u>. Mutual gravitation bring the ball and floor together in one system. As the ball moves downwards, the earth moves upwards, although with an acceleration on the order of 1025 times smaller than that of the ball. The two objects meet, rebound and separate.

5 0
3 years ago
What form of music has two parts and has two contrasting melodies? *
aleksandr82 [10.1K]

Answer: Ternary

Explanation: Ternary Form also has two parts, but is different from Binary Form. Relevance. Ternary form, sometimes called song form, is a three-part musical form where the first section (A) is repeated after the second section (B) ends. different words and same music.

Please mark as brainliest!

5 0
2 years ago
Other questions:
  • An electron in the n = 6 level of the hydrogen atom relaxes to a lower energy level, emitting light of λ = 93.8 nm .find the pri
    14·2 answers
  • The weight of the block in the drawing is 97.0 N. The coefficient of static friction between the block and the vertical wall is
    15·1 answer
  • What is question 10—20 PTS!!
    9·1 answer
  • Why does the liquid rise up through the dip tube when the valve is open
    11·2 answers
  • What in the world is infrared radiation
    14·1 answer
  • You are on a train moving east at 100 meters/second. You run down the aisle at 10 meters/second. If you are running in the same
    6·1 answer
  • 8. Humans need oxygen to break down food in order to provide energy for cells. The oxygen needed for this process is delivered b
    8·2 answers
  • How do newtons three laws of motion work
    13·1 answer
  • A(n) ________ is a thick accumulation of sediments and small tectonic blocks formed of material scraped off subducting oceanic l
    6·1 answer
  • What is common between transverse waves and longitudinal waves?
    13·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!