Answer:
-320 μJ.
Explanation:
Consider a point with an electrical charge of 
. Assume that 
is the electrical potential at the position of that charge. The electrical potential of that point charge will be equal to:
.
Keep in mind that since both and might not be positive, the size of the electrical potential energy might not be positive, either.
For this point charge,
; (that's -8.0 microjoules, which equals to 
)
.
Hence its electrical potential energy:
.
Why is this value negative? The electrical potential energy of a charge is equal to the work needed to bring that charge from infinitely far away all the way to its current position. Also, negative charges are attracted towards regions of high electrical potential. Bringing this 
negative charge to the origin will not require any external work. Instead, this process will release 320 μJ of energy. As a result, the electrical potential energy is a negative value.
The mechanical efficiency = actual work / ideal work
So ζ = 1540 / 1600 * 100% = 96.25%
Answer and Explanation:
Data provided in the question
Force = 50N
Length = 5mm
diameter = 2.0m = 
Extended by = 0.25mm = 
Based on the above information, the calculation is as follows
a. The Stress of the wire is
here area of circle = perpendicular to the are i.e cross-sectional i.e
= 
= 
Now place these above values to the above formula
= 15.92 MPa
As 1Pa = 1 by N m^2
So,
MPa = 10^6 N m^2
b. Now the strain of the wire is
= 
The red, yellow, and green wavelengths of sunlight are absorbed by water molecules in the ocean. ... In coastal areas, runoff from rivers, resuspension of sand and silt from the bottom by tides, waves and storms and a number of other substances can change the color of the near-shore waters.
