00:01
We have two copper metals here.
00:03
However, wire one has twice the cross -section area of wire two, and wire two is twice the length of wire one.
00:13
They are both made of copper, so the resistivity of the two wires are identical.
00:19
So we are to determine the resistance of the second copper wire.
00:23
We can answer the question by applying the definition of resistance of wire in terms of length, cross -sectional area, and the identity of that wire.
00:34
Knowing that the two wires are made of the same substance, which is copper, then we can see that the resistivity here is constant.
00:43
So we can now establish the relationship between resistance and the length of the wire and resistance and the cross -sectional area of the wire.
00:51
So as you can see, since resistance is a numerator and the length is also a numerator, then we can see that resistance is directly proportional to the length.
01:04
So on the other hand, resistance here is in the numerator, but the cross -section area is the denominator.
01:14
So there is a linear but inverse relationship between cross -sectional area and wire resistance.
01:22
So using this, we can now compare the lengths and the cross -section area of, r2 with respect to r1...