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20 Physics -- DC Circuits

A wire is stretched to double it's length. What happens to its resistance and resistivity ? 

A wire is stretched to double it's length. What happens to its resistance and resistivity ? 

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When a wire is stretched to double its length while maintaining its original cross-sectional area, the resistance of the wire increases, but the resistivity remains unchanged. 


The resistance of a wire is directly proportional to its length. By doubling the length of the wire, the resistance also doubles. This relationship is given by the formula R = ρL/A, where R is the resistance, ρ is the resistivity, L is the length, and A is the cross-sectional area.


However, the resistivity of a material is an intrinsic property that depends on the material's composition and temperature. It does not change when the wire is stretched.

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What is the smallest number of 1Ω resistors needed such that when arranged in a certain arrangement involving only series and parallel connections, that the equivalent resistance is (7/6)Ω?

A storage battery of emf 8V and internal resistance 0.5ohm is discharged through a parallel combination of to resistor each of resistance 15 ohm. What is the terminal voltage of the battery?​ [3]a)...

Emf =8V,

Internal resistance r=0.5Ω
R1 = R2 = 15 Ω

Equivalent capacitance of R1 and R2 is

R= 7.5 Ω

now,

emf = I (R+r)
8 = I (7.5+0.5)

8 = I 8
I = 1A

Now,

E= IR+ Ir
E = V + Ir
8 = V + 1x0.5

V= 7.5 volt


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A wire is stretched to double its length. what happens to its resistivity???

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