Question

of the percentage change in length is ar and
Percentage change in radice is 3% of a circular
cross sectional wire then find the percentage
change in resistance​

Answer 1

Answer:

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Explanation:

Answer 2

Answer:

If the length of a wire is stretched by 20 percent, what is the percentage of change in new resistance?

If the length of a wire is stretched by 20 percent, what is percentage of change in new resistance?

Let the original length of the wire be l and its original area of cross-section be a and its original resistance be R, where R = (resistivity) l/a.

After stretching the new length becomes l', where l' = 1.2 l;==> l'/l = 1.2 ——————(1)

Let the new area of cross-section be a'. In strenching when the length increase, the area of cross-section must decrease appropriately to conseve volume. Assuming uniform area of cross-section a' we have;

a' × l' = a × l ; ==> a' = a × l/l' = a × l /1.2 l = a/1.2——-(2)

Let the new resistance of the stretched wire be R'. Then

R' = (resistivity) l'/a' = (resistivity)×( 1.2 l/ a) × 1.2 = 1.2² × (resistivity)× l/a = 1.44 R

Change in resistance in stretching = 1.44 R - R = 0.44 R

Therefore percentage change in resistance = [(Change in resistance) ÷ (original resistance)]×100= (0.44 R/R)× 100 = 44

Explanation:

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