A 10 ohm thick wire is drawn into a thin wire so that its length becomes three times . calculate its new resistance
Answers
Answered by
74
Formula for resistance is as follows:
resistance(R) = restivity(r) x Length (L)/ Area (A)
R=rL/A
When the length increases by three, the cross section will reduce by three. Hence;
the Length will be 3L
while area= A/3
New resistance will be r3L/(A/3) = r9L/A
If rL/A = 10ohms
Then 9(rL/A)= 10 x9 rL/A x(A/rL)
=90
Therefore the new resistance = 90ohm
resistance(R) = restivity(r) x Length (L)/ Area (A)
R=rL/A
When the length increases by three, the cross section will reduce by three. Hence;
the Length will be 3L
while area= A/3
New resistance will be r3L/(A/3) = r9L/A
If rL/A = 10ohms
Then 9(rL/A)= 10 x9 rL/A x(A/rL)
=90
Therefore the new resistance = 90ohm
Answered by
11
Answer:
90 ohm
Explanation:
L=3L
A=A/3
R=rl /A
r3L3/A=9rl/A
As per given rl/A=10ohm
9rl/A=9×10
=90ohm
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