Answer:
t = 5.59x10⁴ y
Explanation:
To calculate the time for the ¹⁴C drops to 1.02 decays/h, we need to use the next equation:
(1)
<em>where 
: is the number of decays with time, A₀: is the initial activity, λ: is the decay constant and t: is the time.</em>
To find A₀ we can use the following equation:
(2)
<em>where N₀: is the initial number of particles of ¹⁴C in the 1.03g of the trees carbon </em>
From equation (2), the N₀ of the ¹⁴C in the trees carbon can be calculated as follows:
<em>where 
: is the tree's carbon mass, 
: is the Avogadro's number and 
: is the ¹²C mass. </em>
Similarly, from equation (2) λ is:
<em>where t 1/2: is the half-life of ¹⁴C= 5700 years </em>
So, the initial activity A₀ is:
Finally, we can calculate the time from equation (1):
I hope it helps you!
Answer:
Explanation:
Field lines are lines of forces around a bar magnet. The show the direction of force field in a magnet.
Usually, around a bar magnet, the field lines originates and spreads out from the north pole.
Then they converge and enter through the south pole.
Therefore, we can make our choice by inspecting the given diagram. If the lines enters through the pole, it is the south pole.
Where they originate or leave is the north pole.
Speed has the dimensions of distance divided by time. The SI unit of speed is themetre<span> per second, but the most common unit of speed in everyday usage is the kilometre per </span>hour<span> or, in the US and the UK, miles per </span>hour<span>. For air and marine travel the knot is commonly used.</span>
