After a plant or animal dies the 14c content decreases with a half-life of 5730 years. if an archaeologist finds an ancient firepit containing partially consumed firewood, and the 14c content of the wood is only 15.5% that of an equal carbon sample from a present-day tree, what is the age (in years) of the ancient site?

age of the site is 15411.75 years old

Explanation:

Given data

plant or animal dies = 14C

time period = 5730 year

carbon = 15.5%

to find out

age (in years) of the ancient site

solution

we know that Final value = Initial value  ×

here n is half life passed

so for 15.5%

15.5% = 100% of  

0.155 = 1 ×

now take log both side

log 0.155 = log  

n = log 0.155 / log 0.5

n = 2.68966

we know here  5730 years in half life

so for 2.68966 half-lives = 2.68966 × 5730  =  15411.7518

age of the site is 15411.75 years old

continuous conducting path for current, power supply

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.