Heavy-duty cords will have a marking on the insulation such as letters which indicates its properties.
<h3>What are Heavy duty cords?</h3>
Heavy duty cords comprises of insulators which helps prevent cases of electric shock. There are usually letters written on them which indicates the nature of insulation and other properties.
For example, the "S" in "SO" stands for "Extra Hard Service and the "O" stands for oil resistant.
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A situation that involves the transfer of heat by means of convection must involve the exchange of fluid currents such as land and sea breezes.
Heat transfer by convection is a method of heat transfer by which heat is transferred between two bodies through through currents of moving fluids or gases.
The following are examples of heat transfer by convection;
- land breezes cooling the sea at night
- sea breezes cooling the land during the day
- boiling of water
- circulation of blood, etc
Thus, a situation that involves the transfer of heat by means of convection must involve the exchange of fluid currents such as land and sea breezes.
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Answer:
Explanation:
From the information given;
The surface area of a sphere = 
If the sphere is from the collection of spherical shells of infinitesimal thickness = dr
Then,
the volume of the thickness and the sphere is;
V = 
Using Gauss Law
here,
q(r) =charge built up contained in radius r
since we are talking about collections of spherical shells, to work required for the next spherical shell r +dr is
where;
dq which is the charge contained in the next shell of charge
here dq = volume of the shell multiply by the density
equating it all together
Integration the work required from the initial radius r to the final radius R, we get;
![U = \int^R_0 \dfrac{16 \pi^2 \ k_c \rho^2}{3} [\dfrac{r^5}{5}]^R_0](https://tex.z-dn.net/?f=U%20%3D%20%5Cint%5ER_0%20%20%5Cdfrac%7B16%20%5Cpi%5E2%20%5C%20k_c%20%5Crho%5E2%7D%7B3%7D%20%5B%5Cdfrac%7Br%5E5%7D%7B5%7D%5D%5ER_0)
Recall that:
the total charge on a sphere, i.e 
Then :
