The half-life is simply the amount of time it takes for half of the isotope to decay into something else.
<span>After 1 half-life, half of the original sample remains. After a second half-life, half of that part remains or 1/4 of the original....after 3 half-lives, 1/8 remains and so on. </span>
<span>In your example, ut started with 8 billion atoms. After one half-life, there was 4 billion. After a second half-life, there was 2 billion and after 3, one billion remain.</span>
After 1 half-life, half of the original sample remains. After a second half-life, half of that part remains or 1/4 of the original....after 3 half-lives, 1/8 remains and so on.
In yor example, ut started with 8 billion atoms. After one half-life, there was 4 billion. After a second half-life, there was 2 billion and after 3, one billion remain.
From the attached file diagram, the total force acting on the charged box is the downward weight and the repulsive force acting in opposite to the weight force . Hence we can write the total force as
1. An ideal ammeter has very small or almost zero resistance. As the resistance is small the maximum current can pass through the ammeter which it can read it.
2. An ideal voltmeter has very large or infinite resistance. As the resistance is very large so the maximum voltage drops across the resistor and gives the accurate reading.
