Wire of resitance r is drawn double its length. Find new resistance
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If a wire is stretched to double its length, what will its new resistance be?
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Sreehari
Answered Mar 30
Originally Answered: What happens to the resistance of the wire when the length is doubled?
The Resistance will actually get doubled provided other factors like temperature, type and condition remains the same.
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Naveen, studied at Anna University, Tamil Nadu, India
Answered Oct 30, 2017
The new resistance of the wire becomes four times its old resistance.
The wire’s length is stretched to twice its length I.e. area of cross section decreases or becomes half, since volume remains the same.
R= (row*L)/A
row - specific resistance
L - length of wire
A- Area of cross section wire
Ur condition
New R= (row*2L)/(new A)
new A = old A/2 as per below derivation
Hence new R = (row*2L)/(A/2)
New R = 4*( (row*L)/A))=4*old R
————————————
For area and length relation
Volume of cylinder =pi*r*r*L=A*L
r - radius of flat surface or tip of wire.
A=area of cross section
A=pi*r*r
Answer
6667
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91 ANSWERS

Sreehari
Answered Mar 30
Originally Answered: What happens to the resistance of the wire when the length is doubled?
The Resistance will actually get doubled provided other factors like temperature, type and condition remains the same.
627 Views · View Upvoters
Upvote· 12
Share
Comment...

Naveen, studied at Anna University, Tamil Nadu, India
Answered Oct 30, 2017
The new resistance of the wire becomes four times its old resistance.
The wire’s length is stretched to twice its length I.e. area of cross section decreases or becomes half, since volume remains the same.
R= (row*L)/A
row - specific resistance
L - length of wire
A- Area of cross section wire
Ur condition
New R= (row*2L)/(new A)
new A = old A/2 as per below derivation
Hence new R = (row*2L)/(A/2)
New R = 4*( (row*L)/A))=4*old R
————————————
For area and length relation
Volume of cylinder =pi*r*r*L=A*L
r - radius of flat surface or tip of wire.
A=area of cross section
A=pi*r*r
Answered by
0
If a wire is stretched to double its length then
L is the length of the conductor and
A is the area of the conductor
When wire is stretched to double its length its area of cross section decreases to half of its value.
New length, l'=2l
Thus, new resistan is four times
L is the length of the conductor and
A is the area of the conductor
When wire is stretched to double its length its area of cross section decreases to half of its value.
New length, l'=2l
Thus, new resistan is four times
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