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
soldi70 [24.7K]
3 years ago
5

When time is measured in​ days, the decay constant for a particular radioactive isotope is 0.16. Determine the time required for

a confined sample of the isotope to fall to 80​% of its original value.
Physics
2 answers:
Brums [2.3K]3 years ago
8 0

Answer:

t = 1.4 days

Explanation:

The law of radioactive decay gives the amount of radioactive substance, left after a certain amount of time has passed. The formula of law of radioactive decay is given as follows:

N = N₀ (e)^-λt

where,

λ = decay constant = 0.16

N₀ = Initial Amount of the Substance

N = The Amount of Substance Left after Decay = 80% of N₀ = 0.8 N₀

t = Time Required by the Substance to decay to final value = ?

Substituting these values in the law of radioactive decay formula, we get:

0.8 N₀ = N₀ (e)^-0.16 t

0.8 = (e)^-0.16 t

ln (0.8) = -0.16 t

t = - 0.2231/-0.16

<u>t = 1.4 days</u>

san4es73 [151]3 years ago
5 0

Answer:

The time take is  t = 1.3964 \ days

Explanation:

From the question we are told that

    The decay constant is  \lambda  = 0.16

     The percentage fall is  c =  0.80

The equation for radioactive decay is mathematically represented as

               N(t) =  N_o  * e^{- \lambda t  }

Where is N(t) is the new amount of the new the isotope while N_o is the original

At initial  N_o =  100%  = 1

At N(t ) =  80%  = 0.80  

       0.80 =  1 * e^{- 0.16 t }

=>     -0.223 =  -0.16 t

=>     t = 1.3964 \ days

You might be interested in
Find the following answer based on the image.
saul85 [17]

<u>We are given:</u>

Mass of Neptune = 1.03 * 10²⁶ kg

Distance from the center of Neptune (r) = 2.27 * 10⁷

now, computing the value of the acceleration due to gravity (g)

<u>Finding g:</u>

We know the formula:

g = G(mass of planet) / (r)²

g = [6.67 * 10⁻¹¹ * 1.03*10²⁶] / (2.27*10⁷)                      [since G is 6.67*10⁻¹¹]

g = (6.87 * 10¹⁵) / (5.15 * 10¹⁴)

which can be rewritten as:

g = (6.87 * 10¹⁵ * 10⁻¹⁴) / 5.15

g = (6.87 * 10¹⁵⁻¹⁴) / 5.15

g = (6.87/5.15) * 10

g = 1.34 * 10

g = 13.4 m/s² <em>(approx)</em>

5 0
3 years ago
What is a vernier caliper used for?​
iris [78.8K]

me ajudem por favor pra agora de noite

5 0
3 years ago
g A 1.5-kg mass attached to spring with a force constant of 20.0 N/m oscillates on a horizontal, frictionless track. At t = 0, t
jok3333 [9.3K]

Answer:

(a)    f = 0.58Hz

(b)    vmax = 0.364m/s

(c)    amax = 1.32m/s^2

(d)    E = 0.1J

(e)    x(t)=0.1m*cos(2π(0.58s^{-1})t)

Explanation:

(a) The frequency of the oscillation, in a spring-mass system, is calculated by using the following formula:

f=\frac{1}{2\pi}\sqrt{\frac{k}{m}}            (1)

k: spring constant = 20.0N/m

m: mass = 1.5kg

you replace the values of m and k for getting f:

f=\frac{1}{2\pi}\sqrt{\frac{20.0N/m}{1.5kg}}=0.58s^{-1}=0.58Hz

The frequency of the oscillation is 0.58Hz

(b) The maximum speed is given by the following relation:

v_{max}=\omega A=2\pi f A      (2)

A: amplitude of the oscillations = 10.0cm = 0.10m

v_{max}=2\pi (0.58s^{-1})(0.10m)=0.364\frac{m}{s}

The maximum speed of the mass is 0.364 m/s.

The maximum speed occurs when the mass passes trough the equilibrium point of the oscillation.

(c) The maximum acceleration is given by the following formula:

a_{max}=\omega^2A=(2\pi f)^2 A

a_{max}=(2\pi (0.58s^{-1}))(0.10m)=1.32\frac{m}{s^2}

The maximum acceleration is 1.32 m/s^2

The maximum acceleration occurs where the elastic force is a maximum, that is, where the mass is at the maximum distance from the equilibrium point, that is, the acceleration.

(d) The total energy of the system is calculated with the maximum potential elastic energy:

E=\frac{1}{2}kA^2=\frac{1}{2}(20.0N/m)(0.10m)^2=0.1J

The total energy is 0.1J

(e) The displacement as a function of time is:

x(t)=Acos(\omega t)=Acos(2\pi ft)\\\\x(t)=0.1m\ cos(2\pi(0.58s^{-1})t)

6 0
3 years ago
What was significant about the discovery of gallium
Kryger [21]
It confirmed medeleeve's hypothesis (prediction) and showed the use of his table
8 0
3 years ago
Read 2 more answers
In a wheel and axle, the radius of the wheel is 20 cm and the radius of the axle is 4 cm. What is the mechanical advantage?
aliya0001 [1]
The answer is 5. To find the advantage you just divide 20 by 4.
4 0
3 years ago
Read 2 more answers
Other questions:
  • The image of a distant tree is virtual and very small when viewed in a curved mirror. The image appears to be 22.9 cm behind the
    11·2 answers
  • Imagine two people standing at placemark A and placemark E, looking at each other across the fault. Which of the following state
    7·1 answer
  • Law of conservation of energy states that
    5·2 answers
  • A solid metal sphere of diameter D is spinning in a gravity-free region of space with an angular velocity of ω. The sphere is sl
    7·1 answer
  • A main difference between gravitational and electric forces is that electrical forces
    14·1 answer
  • 2.
    15·1 answer
  • A ______ employs a weight and a wire to detect horizontal movement.
    10·2 answers
  • At do we call the cells that are made as the end result<br> of meiosis?
    12·1 answer
  • A mustang, has an average velocity of 33 m/s while covering a course that is 21 miles long. (1 mile = 1609 m). How long did it t
    10·1 answer
  • A plant dying after being exposed to poison represents a physical change.
    6·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!