Radioactive decay is given by:
N = No x e^(-λt)
We know that N/No has to be 0.05
λ = 0.15
0.05 = e^(-0.15t)
t = ln(0.05)/(-0.15)
t = 19.97 days
Answer:
new force is 6 times of the initial force.
Explanation:
Let the charges on two objects is q₁ and q₂. The electric force between charges is given by :

Objects 1 and 2 attract each other with a electrostatic force of 18.0 units
If the charge of Object 1 is doubled and the charge of object 2 is tripled, it means,
and
. New force is given by :

So, the new electrostatic force between objects will become 6 times of the initial force.