00:01
Question number four.
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What happens to the resistance of conductor whose cross -sectional area is halved and the length is doubled? we are given four options here.
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So answer the question, we can use the definition of the resistance of a conductor.
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So we have it here in blue ink, where greek letter row is the resistivity of the material.
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L is for length and a is for the cross -sectional area.
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Written in red ink is the illustration of the original situation.
00:34
So what if we decrease the cross -sectional area by half? so the original a will become one half of the original.
00:44
Hence the wire will be more or less one half as big as it was before.
00:51
And the length is doubled.
00:53
So we need to, okay, this is now the new conductor, more or less.
01:00
Where the length has become 2l.
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So what effect will these two changes have on the resistance? let's look at the equation for the relationship among resistance, length, and area here...