Answer:60 ohms
Explanation:
R1=30 ohms
R2=15 ohms
R3=15 ohms
Let the total resistance be R
R=R1 + R2 + R3
R=30 + 15 +15
R=60
Total resistance is 60 ohms
Answer:
The correct answer is 
Explanation:
The formula for the electron drift speed is given as follows,

where n is the number of of electrons per unit m³, q is the charge on an electron and A is the cross-sectional area of the copper wire and I is the current. We see that we already have A , q and I. The only thing left to calculate is the electron density n that is the number of electrons per unit volume.
Using the information provided in the question we can see that the number of moles of copper atoms in a cm³ of volume of the conductor is
. Converting this number to m³ using very elementary unit conversion we get
. If we multiply this number by the Avagardo number which is the number of atoms per mol of any gas , we get the number of atoms per m³ which in this case is equal to the number of electron per m³ because one electron per atom of copper contribute to the current. So we get,

if we convert the area from mm³ to m³ we get
.So now that we have n, we plug in all the values of A ,I ,q and n into the main equation to obtain,

which is our final answer.
It should be 0.25kg because you converter from g to kg and since 1g<1kg so you move the decimal to the left
C- 10ft. Hope this helped. Have a great day! :D