a wire having resistance of 3 ohm is stretched to double of its initial lenght calculate the new resistance of the wire
Answers
Answered by
1
Explanation:
ANSWER
Given: a wire of resistance 1Ωis stretched to double its length.
To find the new resistance
Solution:
Here,
R=1Ω,Length=L,Cross sectional area, CSA=A
The formula used is,
R=ρ
A
L
⟹ρ
A
L
=1..........(i)
The new length, L
′
=2L
And new CSA = A
′
So we have,
Volume of the wire= AL
Now after the act of stretching the volume remains constant.
Therefore, AL=A
′
L
′
⟹AL=2LA
′
⟹A
′
=
2
A
Now the new resistance of the wire becomes
R
new
=ρ
A
′
L
′
⟹R
new
=ρ
2
A
2L
⟹R
new
=4ρ
A
L
R
new
=4×1 by using equation (i)
Therefore the new resistance is 4Ω
Answered by
1
Explanation:
Resistance,R = pl/A
where,
1) p = resistivity of the wire
2) l = length of wire
3) A= cross section of the wire
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