A wire of length = l and resistance = R , if it streched such that its length becomes 3 times more of its initial one. Find the ratio of initial resistance to the newly obtained resistance.
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1:3 is the required answer
Explanation:
According to the Question
It is given that ,
Length of wire = l
Resistance ,R
Resistance in 1st case :-
R = ρl/A
where
R denote Resistance
ρ denote electrical resistivity
l denote length of wire
A denote Area of cross section .
→ R = ρl/A ------------(i)
Again in second case the wire is stretched such that it's length become 3 times as initial was .
New length of Wire = 3l
Resistance in 2nd case :-
→ R = ρ3l/A -----------(ii)
From equation (i) & (ii) we get
→ ρl/A = ρ3l/A
→ l = 3l
→ 1 = 3
Hence, the ratio of initial resistance to the newly obtained resistance will be 1:3 .
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