20% would be probably right cuz 100% is total and 80+ what gives u 100 which is 20
<u>Answer:</u> The remaining sample of X is 6.9 grams.
<u>Explanation:</u>
All the radioactive reactions follow first order kinetics.
The equation used to calculate rate constant from given half life for first order kinetics:

We are given:

Putting values in above equation, we get:

The equation used to calculate time period follows:

where,
= initial mass of sample X = 78 g
N = remaining mass of sample X = ? g
t = time = 16.5 min
k = rate constant = 
Putting values in above equation, we get:

Hence, the remaining amount of sample X is 6.9 g
Every one has a reason in life. You may not know what it is just yet, but you do.
Answer:
For electric field inside cylinder, check image 02 attached
For electric field outside cylinder, check image 03 attached
Explanation:
Let's consider the polarized cylinder as superposition of two cylinders with opposite,equal, uniform charge densities in a way shown in the figure in the "image 01"d attached ;
In general, if we have an object with polarization (P¬) , then we have to take two objects with similar shape to the system, with opposite, equal, and uniform charge densities and then we super-impose these two objects in such a way that the total dipole moment of this superimposed system is equal to the total dipole moment of original system.
Now, we can take the super- imposed system as equivalent to the original system for calculating electric field and potential.
Therefore,
For the electric field inside the cylinder, check the solution in "image 02" i attached
For the electric field outside the cylinder, check, "image 03" i attached.
The force of the object with the given mass and acceleration is determined as 10 N.
<h3>
Force of the object</h3>
The force of the given object is calculated from Newton's second law of motion as follows;
F = ma
where;
- m is mass of the object = 5 kg
- a is acceleration of the object = 2 m/s²
F = 5 x 2 = 10 N
Thus, the force of the object with the given mass and acceleration is determined as 10 N.
The complete question is below:
Rearranging the equation m = F/a and solve for F, m= 5Kg and a= 2 m\s2
Learn more about force here: brainly.com/question/12970081
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