a resistance
rectangular
An ohmic conductor of circular cross section has a reci
If it is melted and recast to half of its length with rectan
section, its new resistance will be
(1) 2R
(ii) R
(ii) R/2
(iv) R14
Answers
Explanation:
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Secondary School Physics 5 points
An ohmic conductor of circular cross-section has a resistance R. If it is melted and recast to half of its length with rectangular cross-section, its new resistance will be
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Answers
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Answer:
R’= ¼ x R
Explanation:
Resistance of a wire is given as;
R = pL/A
Where p is the resistivity of wire. It will be same for same material
A is the cross sectional area
L is the length.
Now if the wire is recasted, such that the length is halved then, the area will also change because the overall volume has to be the same.
V’=V
A’ x L’ = A x L
When L’ = L/2
This means that area becomes;
A’ = 2 x A
Calculating new resistance of wire after it is recasted;
R’ = pL"/A"
R’ = p (L/2)⁄2A
R’= p L/4A
R’= ¼ x R
Answer:
r/4 will be its new resistance
as R is directly proportional to area and inversly proportional to lenght