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3 years ago

What is your name in face book

Engineering

2 answers:

harina [27]3 years ago

8 0

Answer:

<h2>Please dear user,⚠️</h2>

<h2>Stop asking nonsense question for free⚠️</h2>

<h2>Brainly app is an app that helps students from their homeworks⚠️</h2>

<h2>Or you'll get banned⚠️</h2>

nekit [7.7K]3 years ago

4 0

Answer:

Why do you want to know...?

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3 years ago

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2 years ago

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A wastewater is to be disinfected using ultraviolet (UV) light. Batch experiments find that the bacterial concentration decays u

Ksivusya [100]

Answer:

k = 0.1118 per min

Explanation:

Assume;

Initial number of bacteria = N0

Number of bacteria IN 'T' time = Nt

So,

$Nt=N0e^{-kt}\\\\in\ 6.2 min\\\\\\frac{N0}{2}= N0e^{-k(6.2)}\\\\ln\frac{1}{2} = -k[6.2]$

k = 0.1118 per min

7 0

3 years ago

Refrigerant-134a is throttled from the saturated liquid state at 800 kPa to a pressure of 140 kPa. Determine the temperature dro

zavuch27 [327]

Answer:

The temperature drop is 61.1 °C

The final specific volume of the refrigerant is 1.236 m^3/kg

Explanation:

Initial pressure of refrigerant = 800 kPa = 800/100 = 8 bar

Final pressure of refrigerant = 140 kPa = 140/100 = 1.4 bar

From steam table

At 8 bar, initial saturated temperature is 170.4 °C

At 1.4 bar, final saturated temperature is 109.3 °C

Temperature drop = initial saturated temperature - final saturated temperature = 170.4 - 109.3 = 61.1 °C

Also, from steam table

At 1.4 bar, specific volume is 1.236 m^3/kg

Final specific volume of the refrigerant is 1.236 m^3/kg

5 0

3 years ago

"Carbon 14 (C-14), a radioactive isotope of carbon, has a half-life of 5730 ± 40 years. Measuring the amount of this isotope lef

igor_vitrenko [27]

Answer:

The age of the bones is approximately 14172 years.

Explanation:

The age of the bones can be determinated using the following decay equation:

$N_{(t)} = N_{0}e^{-\lambda t}$ (1)

<u>Where:</u>

N(t): is the quantity of C-14 at time t

No: is the initial quantity of C-14

λ: is the decay rate

t: is the time

First, we need to find λ:

$\lambda = \frac{ln(2)}{t_{1/2}}$

<u>Where:</u>

t(1/2): is the half-life of C-14 = 5730 y

$\lambda = \frac{ln(2)}{5730 y} = 1.21 \cdot 10^{-04} y^{-1}$

Now, we can calculate the age of the bones by solving equation (1) for t:

$t = \frac{-ln(\frac{N_{(t)}}{N_{0}})}{\lambda}$

We know that the bones have lost 82% of the C-14 they originally contained, so:

$N_{t} = (1 - 0.82)N_{0} = 0.18N_{0}$

$t = \frac{-ln(0.18)}{1.21 \cdot 10^{-04} y^{-1}}$

$t = 14172 y$

Therefore, the age of the bones is approximately 14172 years.

I hope it helps you!

3 0

3 years ago

What is your name in face book​

What is your name in face book