00:01
In this question, the objective is to calculate the dc resistance in oms per kilometer of an aluminum conductor composed of 37 strands.
00:12
So the number of strands is denoted by n and this will be here 37.
00:18
Then the diameter of each strand will be equal to 0 .33 centimeter or in terms of meter it can be written as 0 .00.
00:30
Now it will be 3 -3 meter, then the aluminum resistivity at 75 degrees celsius will be here equals to it is 3 .2, then it will be multiplied with 10 -raged to the power negative 8 oom meter.
00:48
So now let us write the increase in resistance due to spiraling.
00:54
So the increase in resistance is 2 percentage.
00:58
So it will be i -n -c -r -e -a -s -e.
01:03
So let us first calculate the value of area of cross -section of a circular strand.
01:10
So area will be equals to pi, then it is d divided by 2, raised to the power 2.
01:17
So this value will be pi multiplied with 0 .033, and in the denominator it is here 4.
01:26
So it will be raised to the power 2 and then the value of a, that is area, will be approximately 8 .55 and then it is multiplied with 10 raised to the power negative 6 and here it will be meter square.
01:44
So it's time to calculate the total area of the conductor and the total area of the conductor will be equals to n multiplied with a.
01:56
The conductor is made up of 37 strands and each strands is having an area of 8 .55 multiplied with 10 raised to the power negative 6.
02:08
So it is equal to 37.
02:11
Now it will be 8 .55 and then we can write 10 raise to the power negative 6 and the value of a total that is total area will be equal to 3 .16...