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3 years ago

GRAPH INCLUDED PLEASE HELP

Physics

1 answer:

swat323 years ago

5 0

Answer:

10 days

Explanation:

The half-life of a radioactive sample is the time taken for half of the sample to decay.

In the diagram, the half-life corresponds to the time after which the % of cobalt-57 has halved. We can observe the following:

At t=10 days, the % of Co remaining is approximately 45%

At t=20 days, the % of Co remaining is approximately 22%

This means that the sample of cobalt-57 has halved in 10 days, so the half-life of cobalt-57 is 10 days.

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Air conditioners operate on the same principle as refrigerators. Consider an air conditioner that has 7.00 kg of refrigerant flo

kozerog [31]

Answer:

5.15J

Explanation:

First. 54% of the 7kg refrigerant is liquid

So we find mass of vapour at inlet generator

M1 = ( 1-0.54)*7= 3.2kg

At compressor mass of vapour will be

M2= 0.95*7= 6.7kg

So the Mass of vapour at exit generator is

M2-M1= 3.5kg

So to find heat absorbed by refrigerant in evaporation

Its using

Q= mh

°= 3.5x 1.50×10^5 J/kg

=5.15J

4 0

3 years ago

Can you help me ASAPPP please help me

AveGali [126]

Answer:it is a

Explanation hope this helps .

6 0

3 years ago

What change in entropy occurs when a 0.15 kg ice cube at -18 °C is transformed into steam at 120 °c 4.

Studentka2010 [4]

Answer: The change in entropy of the given process is 1324.8 J/K

Explanation:

The processes involved in the given problem are:

$1.)H_2O(s)(-18^oC,255K)\rightarrow H_2O(s)(0^oC,273K)\\2.)H_2O(s)(0^oC,273K)\rightarrow H_2O(l)(0^oC,273K)\\3.)H_2O(l)(0^oC,273K)\rightarrow H_2O(l)(100^oC,373K)\\4.)H_2O(l)(100^oC,373K)\rightarrow H_2O(g)(100^oC,373K)\\5.)H_2O(g)(100^oC,373K)\rightarrow H_2O(g)(120^oC,393K)$

Pressure is taken as constant.

To calculate the entropy change for same phase at different temperature, we use the equation:

$\Delta S=m\times C_{p,m}\times \ln (\frac{T_2}{T_1})$ .......(1)

where,

$\Delta S$ = Entropy change

$C_{p,m}$ = specific heat capacity of medium

m = mass of ice = 0.15 kg = 150 g (Conversion factor: 1 kg = 1000 g)

$T_2$ = final temperature

$T_1$ = initial temperature

To calculate the entropy change for different phase at same temperature, we use the equation:

$\Delta S=m\times \frac{\Delta H_{f,v}}{T}$ .......(2)

where,

$\Delta S$ = Entropy change

m = mass of ice

$\Delta H_{f,v}$ = enthalpy of fusion of vaporization

T = temperature of the system

Calculating the entropy change for each process:

For process 1:

We are given:

$m=150g\\C_{p,s}=2.06J/gK\\T_1=255K\\T_2=273K$

Putting values in equation 1, we get:

$\Delta S_1=150g\times 2.06J/g.K\times \ln(\frac{273K}{255K})\\\\\Delta S_1=21.1J/K$

For process 2:

We are given:

$m=150g\\\Delta H_{fusion}=334.16J/g\\T=273K$

Putting values in equation 2, we get:

$\Delta S_2=\frac{150g\times 334.16J/g}{273K}\\\\\Delta S_2=183.6J/K$

For process 3:

We are given:

$m=150g\\C_{p,l}=4.184J/gK\\T_1=273K\\T_2=373K$

Putting values in equation 1, we get:

$\Delta S_3=150g\times 4.184J/g.K\times \ln(\frac{373K}{273K})\\\\\Delta S_3=195.9J/K$

For process 4:

We are given:

$m=150g\\\Delta H_{vaporization}=2259J/g\\T=373K$

Putting values in equation 2, we get:

$\Delta S_2=\frac{150g\times 2259J/g}{373K}\\\\\Delta S_2=908.4J/K$

For process 5:

We are given:

$m=150g\\C_{p,g}=2.02J/gK\\T_1=373K\\T_2=393K$

Putting values in equation 1, we get:

$\Delta S_5=150g\times 2.02J/g.K\times \ln(\frac{393K}{373K})\\\\\Delta S_5=15.8J/K$

Total entropy change for the process = $\Delta S_1+\Delta S_2+\Delta S_3+\Delta S_4+\Delta S_5$

Total entropy change for the process = $[21.1+183.6+195.9+908.4+15.8]J/K=1324.8J/K$

Hence, the change in entropy of the given process is 1324.8 J/K

4 0

3 years ago

The formula of force is newton and

Arlecino [84]

Answer:

The formula for calculating force is F= Mass × Acceleration

Explanation:

Newton is what force is measured in

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3 years ago

The distance from Earth to the North Star is about 430 light-years. Which of the following statements describes why scientists u

vampirchik [111]

Answer:

Explanation:

7 0

3 years ago