Consider the parallel plates in
[link] . These have equipotential lines that are parallel to the plates in the space between and evenly spaced. An example of this (with sample values) is given in
[link] . We could draw a similar set of equipotential isolines for gravity on the hill shown in
[link] . If the hill has any extent at the same slope, the isolines along that extent would be parallel to each other. Furthermore, in regions of constant slope, the isolines would be evenly spaced. An example of real topographic lines is shown in
[link] .
Calculating equipotential lines
You have seen the equipotential lines of a point charge in
[link] . How do we calculate them? For example, if we have a
charge at the origin, what are the equipotential surfaces at which the potential is (a) 100 V, (b) 50 V, (c) 20 V, and (d) 10 V?
Strategy
Set the equation for the potential of a point charge equal to a constant and solve for the remaining variable(s). Then calculate values as needed.
Solution
In
, let
V be a constant. The only remaining variable is
r ; hence,
. Thus, the equipotential surfaces are spheres about the origin. Their locations are:
;
;
;
.
Significance
This means that equipotential surfaces around a point charge are spheres of constant radius, as shown earlier, with well-defined locations.
Potential difference between oppositely charged parallel plates
Two large conducting plates carry equal and opposite charges, with a surface charge density
of magnitude
as shown in
[link] . The separation between the plates is
. (a) What is the electric field between the plates? (b) What is the potential difference between the plates? (c) What is the distance between equipotential planes which differ by 100 V?
Strategy
(a) Since the plates are described as “large” and the distance between them is not, we will approximate each of them as an infinite plane, and apply the result from Gauss’s law in the previous chapter.
(b) Use
.
(c) Since the electric field is constant, find the ratio of 100 V to the total potential difference; then calculate this fraction of the distance.
Solution
The electric field is directed from the positive to the negative plate as shown in the figure, and its magnitude is given by
To find the potential difference
between the plates, we use a path from the negative to the positive plate that is directed against the field. The displacement vector
and the electric field
are antiparallel so
The potential difference between the positive plate and the negative plate is then
The total potential difference is 500 V, so 1/5 of the distance between the plates will be the distance between 100-V potential differences. The distance between the plates is 6.5 mm, so there will be 1.3 mm between 100-V potential differences.
Significance
You have now seen a numerical calculation of the locations of equipotentials between two charged parallel plates.
Bacteria doesn't produce energy they are dependent upon their substrate in case of lack of nutrients they are able to make spores which helps them to sustain in harsh environments
_Adnan
But not all bacteria make spores, l mean Eukaryotic cells have Mitochondria which acts as powerhouse for them, since bacteria don't have it, what is the substitution for it?
Assimilatory nitrate reduction is a process that occurs in some microorganisms, such as bacteria and archaea, in which nitrate (NO3-) is reduced to nitrite (NO2-), and then further reduced to ammonia (NH3).
Elkana
This process is called assimilatory nitrate reduction because the nitrogen that is produced is incorporated in the cells of microorganisms where it can be used in the synthesis of amino acids and other nitrogen products
There are nothing like emergency disease but there are some common medical emergency which can occur simultaneously like Bleeding,heart attack,Breathing difficulties,severe pain heart stock.Hope you will get my point .Have a nice day ❣️
_Adnan
define infection ,prevention and control
Innocent
I think infection prevention and control is the avoidance of all things we do that gives out break of infections and promotion of health practices that promote life