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3 years ago

3. Sodium-24 has a half-life of 15 hours. If a sample of sodium-24 has an

Physics

1 answer:

sattari [20]3 years ago

3 0

Answer:

See explanation

Explanation:

From the formula;

0.693/t1/2 = 2.303/t log (Ao/A)

t1/2 = half life of Sodium-24

Ao = initial activity of Sodium-24

A= activity of Sodium-24 at time = t

So,

0.693/15 = 2.303/15 log (800/A)

0.0462 = 0.1535 log (800/A)

0.0462/0.1535 = log (800/A)

0.3 = log (800/A)

Antilog(0.3) = (800/A)

1.995 = (800/A)

A = 800/1.995

A = 401 Bq

ii) 0.693/15 = 2.303/30 log (800/A)

0.0462 = 0.0768 log (800/A)

0.0462/0.0768 = log (800/A)

0.6 = log (800/A)

Antilog (0.6) = (800/A)

3.98 = (800/A)

A = 800/3.98

A = 201 Bq

iii)

0.693/15 = 2.303/45 log (800/A)

0.0462 = 0.0512 log (800/A)

0.0462/0.0512 = log (800/A)

0.9 = log (800/A)

Antilog (0.9) = (800/A)

7.94 = (800/A)

A = 800/7.94

A= 100.8 Bq

iv)

0.693/15 = 2.303/60 log (800/A)

0.0462 = 0.038 log (800/A)

0.0462/0.038 = log (800/A)

1.216 = log (800/A)

Antilog(1.216) = (800/A)

16.44 = (800/A)

A = 800/16.44

A = 48.66 Bq

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Review. Consider the deuterium-tritium fusion reaction with the tritium nucleus at rest:

asambeis [7]

Considering the deuterium-tritium fusion reaction with the tritium nucleus at rest: ¹₂H + ¹₃H → ²₄He + ⁰₁n the electric potential energy (in electron volts) at this distance is 17.58MeV

<h3>How is the electric potential energy of deuterium-tritium fusion reaction calculated?</h3>

The reaction is ¹₂H + 1₃H → ²₄He + ⁰₁n

Value of Q = (Mass of ¹₂H + Mass of ¹₃H - Mass of ²₄He- Mass of n) x 931 MeV

Mass of ¹₂H = 2.014102

Mass of ¹₃H = 3.016049

Mass of ²₄He = 4.002603

Mass of n = 1.00867

Therefore Value of Q = [2.014102+3.016049−4.002603−1.00867] × 931 MeV

Therefore Value of Q = 0.01887 × 931 MeV

= 17.58MeV

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brainly.com/question/9054784

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7 0

2 years ago

A fire woman dropped a person onto the safety net. Right

dolphi86 [110]

Answer:

m = 28.7[kg]

Explanation:

To solve this problem we must use the definition of kinetic energy, which can be calculated by means of the following equation.

$E_{k}=\frac{1}{2}*m*v^{2}\\$

where:

Ek = kinetic energy = 1800 [J]

m = mass [kg]

v = 11.2 [m/s]

$1800=\frac{1}{2}*m*(11.2)^{2}\\m = 28.7[kg]$

7 0

3 years ago

Newton’s empirical law of cooling/warming of an object is given by ( ), T Tm k dt dT = − where k is a constant of proportionalit

pychu [463]

Answer:

The time for the cake to cool off to room temperature is

approximately 30 minutes.

Let $T_{0}$ = $70^{0}$ F be the temperature and T that of the body

Explanation:

Our Tm = 70, the initial-value problem is

$\frac{DT}{dt}$ = k(T − 70), T(0) = 300

Solving the equation, we get

$\frac{DT}{t-70}$ = kdt

In [T-70]= kt + $C_{1}$

T = 70 + $C_{2}$ $e^{kt}$

Finding he value for $C_{2}$ using the initial value of T (0)= 300, therefore we get:

300=70+ $C_{2}$

$C_{2}$ = 230 therefore

T= 70+ 230 $e^{kt}$

Finding the value for k using T (3) = 200, therefore we get

T (3) = 200

$e^{3k}$ = $\frac{13}{23}$

K = $\frac{1}{3}$ in $\frac{13}{23}$

= -0.19018

Therefore

T(t) = 70+230 $e^{-0.19018}$

4 0

3 years ago

How does increased pressure result in the formation of a mineral?

drek231 [11]

The best answer is
A) The atoms in the mineral get rearranged

Over time, and under great pressure, the atoms of a substance can become rearranged, forming a new substance. For example, the intense pressure that carbon underground experiences, perhaps in the form of coal, can rearrange the atoms of the substance to create a diamond.

5 0

4 years ago

The 5-kg block A has an initial speed of 5 m/s as it slides down the smooth ramp, after which it collides with the stationary bl

Akimi4 [234]

Answer:

The coupled velocity of both the blocks is 1.92 m/s.

Explanation:

Given that,

Mass of block A, $m_1=5\ kg$

Initial speed of block A, $u_1=5\ m/s$

Mass of block B, $m_2=8\ kg$

Initial speed of block B, $u_2=0$

It is mentioned that if the two blocks couple together after collision. We need to find the common velocity immediately after collision. We know that due to coupling, it becomes the case of inelastic collision. Using the conservation of linear momentum. Let V is the coupled velocity of both the blocks. So,

$m_1u_1+m_2u_2=(m_1+m_2)V\\\\V=\dfrac{m_1u_1+m_2u_2}{(m_1+m_2)}\\\\V=\dfrac{5\times 5+0}{(5+8)}\\\\V=1.92\ m/s$

So, the coupled velocity of both the blocks is 1.92 m/s. Hence, this is the required solution.

8 0

3 years ago