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3 years ago

3. In Figure 2, which object (A, B, or C) has the highest density? Why?

Physics

1 answer:

Ira Lisetskai [31]3 years ago

6 0

Answer: C Because it has more dots in the rectangle meaning that if it has more dots than others then it has a higher density according to the model

Explanation:

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You leave your house at 7:50

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Answer:

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Explanation:

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3 years ago

Read 2 more answers

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

Maurinko [17]

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.

4 0

4 years ago

Answer A B C D and E

harina [27]

Answer:

what is the question I cannot click the

Explanation:

4 0

3 years ago

a) For a given material, would you expect the surface energy to be greater than, the same as, or less than the grain boundary en

sergejj [24]

Answer / Explanation:

To properly answer this question, let us define what a grain boundary is:

A grain boundary is the interface between multiple grains or crystals in a poly-crystalline material. They could also be refereed to as defects in the crystal structure and tend to decrease the electrical and thermal conductivity of structures.

Now, if we refer back to the question asked,

(a) The surface energy is grater than the grain boundary energy because surface atom have fewer bonds than atom along a grain boundary.

Consequentially, the lower the number of bonds formed, the higher the energy

(b) A higher angle grain boundary has higher misalignment and hence greater disruption of bonds (lesser number of bonds) than a small angle grain boundary. Therefore, a high angle grain boundary has higher energy.

7 0

4 years ago

1. What is transferred from place to place by waves?

dem82 [27]

Answer:

Energy

Explanation:

A wave is a disturbance that transfers energy from one place to another without transferring matter. Waves transfer energy away from the source, or starting place, of the energy.

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3 years ago