Answer:
They can be seen from a distance of 4.372 kilometers.
Explanation:
Using the Reyligh creterion for diffraction through a circular aperture we have
where symbol's have their usual meaning
thus applying values we get


Since you are looking for the speed, you need to rearrange the formula which is f = speed / wavelength. That should give you speed = f (wavelength.) All you need to do next is to substitute the value to the following equation. speed = 250 Hz (6.0m) that should leave you with 1500 m/s which is very fast.
D , the e ecosystem would take years to fully restore
Answer:
The age of living tree is 11104 years.
Explanation:
Given that,
Mass of pure carbon = 100 g
Activity of this carbon is = 6.5 decays per second = 6.5 x60 decays/min =390 decays/m
We need to calculate the decay rate
....(I)
Where, N = number of radio active atoms
=half life
We need to calculate the number of radio active atoms
For 

Where,
=Avogadro number


For 



Put the value in the equation (I)


100 g carbon will decay with rate

We need to calculate the total half lives






We need to calculate the age of living tree
Using formula of age



Hence, The age of living tree is 11104 years.