2 years ago

If the radius of a coin is 14 cm, What is surface area?

1 answer:

5 0

Let R=radius

Surface area of coin = π r²
where π can be typed in scientific calculator

Answer: π x 14 x 14 = 615.752 cm²

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zysi [14]

K=+1

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That’s it!!!

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3 years ago

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ololo11 [35]

Reaction [taking place]

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3 years ago

Flourine is found to undergo 10% radioactivity decay in 366 minutes determine its halflife

yuradex [85]

Answer:

$\boxed{\text{2408 min}}$

Explanation:

The integrated rate law for radioactive decay is

$\ln\dfrac{N_{0}}{N_{t}} = kt$

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$\begin{array}{rcl}\ln \dfrac{100}{90} & = & k \times 366\\\\1.054 & = & 366k\\\\k & = & \dfrac{1.054 }{366}\\\\k & = & 2.879 \times 10^{-4} \text{ min}^{-1}\\\end{array}\\\\$

2. Calculate the half-life

$t_{\frac{1}{2}} = \dfrac{\ln2}{k}\\\\t_{\frac{1}{2}} = \dfrac{\ln2}{2.879 \times 10^{-4} \text{ min}^{-1}} = \text{2408 min}\\\\\text{The half-life for decay is } \boxed{\textbf{2408 min}}$

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3 years ago

When heating a chemical solution over an open flame in a test tube you should - A. keep a cork in the test tube so the solution

Alla [95]

Hello.

The answer is: A. keep a cork in the test tube so the solution cannot spill out

B and C both could be very deadly and it shouldnt be D because if u have an open flame you shouldnt open it even if its not towards anyone.

have a nice day

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3 years ago

Which word completes the blank in the following statement?

Dvinal [7]

The answer should be an electrical circut
i think thats how you spell it

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