Half life is the time that it takes for half of the original value of some amount of a radioactive element to decay.
We have the following equation representing the half-life decay:

A is the resulting amount after t time
Ao is the initial amount = 50 mg
t= Elapsed time
t half is the half-life of the substance = 14.3 days
We replace the know values into the equation to have an exponential decay function for a 50mg sample

That would be the answer for a)
To know the P-32 remaining after 84 days we have to replace this value in the equation:

So, after 84 days the P-32 remaining will be 0.85 mg
The given question is incomplete. The complete question is:
A brick has a mass of 4.0 kg and the earth has a mass of
Use this information to answer the questions below. Be sure your answers have the correct number of significant digits. What is the mass of 1 mole of bricks? Round your answer to 2 significant digits. How many moles of bricks have a mass equal to the mass of the Earth? Round your answer to 2 significant digits.
Answer: The mass of 1 mole of bricks is 
2.5 moles of bricks have a mass equal to the mass of the Earth
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to its molecular mass and contains avogadro's number
of particles.
Mass of 1 brick = 4.0 kg = 4000 g (1kg=1000g)
Thus mass of 1 mole of brick or
bricks will be = 
The mass of 1 mole of bricks is 
Now
will correspond to = 1 mole of bricks
will correspond to =
2.5 moles of bricks have a mass equal to the mass of the Earth
Explanation:
bro this question looks like Astrophysics
The only liquid elements at standard temperature and pressure are bromine (Br) and mercury (Hg). Although, elements caesium (Cs), rubidium (Rb), Francium (Fr) and Gallium (Ga) become liquid at or just above room temperature.
Answer:
Answer should be Ernest Rutherford
Explanation:
He was a New Zealand-born British physicist who came to be known as the father of nuclear physics.