Answer:
a) a0 was 46.2 grams
b) It will take 259 years
c) The fossil is 1845 years old
Explanation:
<em>An unknown radioactive substance has a half-life of 3.20hours . If 46.2g of the substance is currently present, what mass A0 was present 8.00 hours ago?</em>
A = A0 * (1/2)^(t/h)
⇒ with A = the final amount = 46.2 grams
⇒ A0 = the original amount
⇒ t = time = 8 hours
⇒ h = half-life time = 3.2 hours
46.2 = Ao*(1/2)^(8/3.2)
Ao = 261.35 grams
<em>Americium-241 is used in some smoke detectors. It is an alpha emitter with a half-life of 432 years. How long will it take in years for 34.0% of an Am-241 sample to decay?</em>
t = (ln(0.66))-0.693) * 432 = 259 years
It will take 259 years
<em>A fossil was analyzed and determined to have a carbon-14 level that is 80% that of living organisms. The half-life of C-14 is 5730 years. How old is the fossil?</em>
<em />
t = (ln(0.80))-0.693) * 5730 = 1845
The fossil is 1845 years old
Answer:
Density of the copper = 8.94g/cm^3
Student A results = 7.3gm/cm^3 ,9.4 gm/cm^3 , 8.3gm/cm^3
Student B results = 8.4 gm/cm^3 , 8.8 gm/cm^3 , 8gm/cm^3
From the observations we conclude that
Student A's result is accurate but not precise as the trials noted are not close to each other.
Student B's result is accurate and precise as the trials noted are close to each other.
Mean density of student A = 7.3 + 9.4 + 8.3 /3 = 8.33gm/cm^3
Mean density of student B = 8.4 + 8.8 + 8 /3 = 8.4 gm/cm^3
both the densities of A and B are 0.5 away from the actual density.
Answer
for number 1 RAIN. Rain is drops of water from clouds. Heavy/ constant/ steady/pouring rain or Downpour is a lot of rain in a short...
SNOW. Snow means atmospheric water vapor frozen into ice crystals and falling in light white flakes or lying on the...
SUN. Blazing means very bright and hot. ... Bright means full of light.
number 2 WEATHER MAPS indicate atmospheric conditions above a large portion of the Earth’s surface. Meteorologists use weather maps to forecast the weather. A HYGROMETER measures the water vapor content of air or humidity. A WEATHER BALLOON measures weather conditions higher up in the atmosphere.
number 3 A climate is an average weather in a given area over a period of time. The weather, on the other hand, can change drastically in a matter of hours. Changing the world takes thousands of years. It is, however, complex and has been growing at an alarming rate in recent years.
Weather refers to how the environment behaves, mostly in terms of its impacts on life and human habits. Temperature, humidity, precipitation, brightness, cloudiness, visibility, wind, and atmospheric pressure all are factors that influence the weather on a daily basis.
