00:01
In this question we have the current in all the three segment that is current at the top current at the middle and current at the bottom which is equals to 9 ampier.
00:10
Now we want to find out the value of a current density j which is equal to y divided by a where i is the current and a is the area that is pi r square or we can write it as a i divided by pi d by two whole square.
00:28
Now therefore we can write the equation for three different points.
00:33
Here we have the diameter at the top which is equal to diameter at the bottom that is 2mm and the diameter at the middle which is equals to 1mm.
00:44
So we can write the current density j at the top which is equal to current density at the bottom which is equal to this i divided by pi r t square plus, sorry, equals to, which is equals to i divided by pi rb square.
01:04
So we can write it as 9 divided by pi multiplied by this 2 divided by 2 multiplied by 2 multiplied by 10 to power minus 3 whole square.
01:13
So on simplification, we get this value of the current density at the top, current density at the bottom which is equals 2 .86 multiplied by 10 to power 6 ampure.
01:27
Per meter square.
01:29
So this is the answer for the first now we can find out the current density at the middle which is equals to i divided by pi rm square so it becomes 9 divided by this pi multiplied by 1mmm so 1 divided by 2 multiplied by 10 to power minus 3 whole square.
01:54
So on simplification of it, we get the value of current density at the middle, which is equals to 11 .45 multiplied by 10 to the power 6, 10 to the power 6 ampere per meter square...