:<span> </span><span>Under the assumption that a cell is made up of two concentric spheres you find the surface are of the inside sphere which will be your A.
You already have your separation and dielectric constant so just use the formula you stated towards the end of your question and you get 8.93x10^-11 Farads which is about 89pF</span>
Answer:
salt water, air and vinegar are homogeneous solutions.
Explanation:
A solution which consists of particles of same proportion is known as a homogeneous solution. Whereas a solution which consists of particles of different proportion is known as a heterogeneous solution.
Salt and water are homogeneous solutions as salt completely disperses in water and forms a clear solution as the particles of salt and water are in proportion.
Air is composed of different gases like nitrogen, oxygen etc are all mixed in fixed ratio. Therefore, air is a homogeneous mixture.
Sand and water are heterogeneous solution as the ration of mixing is different and more over sand particles can be separated from water. Thus, it is not a homogeneous mixture.
Vinegar is also a homogeneous solution as it is composed of acetic acid and water which are mixed in fixed proportion.
Cement is a heterogeneous mixture as it is composed of a number of different substances mixed in different proportions.
Thus, we can conclude that salt water, air and vinegar are homogeneous solutions.
A mixed cost contains a variable element and a fixed element.
Option a
<u>Explanation:</u>
Mixed costs are those costs that has both variable and fixed component. Example: operating cost of a machinery includes fixed costs that cannot be changed with other variable costs like fuel, insurance, depreciation, etc.
It is also named as semi-variable costs. And the formula to calculate mixed cost is as follows,

where,
- y is the "total cost
"
- a is the "fixed cost per period"
- b is the "variable rate per unit of activity"
- x is the "number of units of activity"
Elastic potential energy.
When you stretch a rubber band it has the "potential" to do work, to fly in a given direction. In doing so it changes it's elastic potential energy to kinetic energy.