A 10 ohm thick wire is stretched so that its length becomes three times . Assuming that there is no change in density on stretching. Calculate the resistance of the new wire.
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Answered by
21
Answer:
90 ohm.
Explanation:
The total volume of wire remains the same.
l - previous length
l' - new length= 3l
A- previous area
A'=new area.
l*A=l'*A'. (As volume is constant)
or, l *A= 3l*A
or, A'=A/3
R = k*(l/A). (k is the resistivity)
R'(new resistance) = k*(l'/A').
Dividing the two equations,
R'/R= (l'/A')*(A/l)
A= A'/3
l' = 3l
R' : R = (3l/A)*(A/l)
or, R' : R = 3 * 3
or, R' = 9 * 10 ohm. (R = 10 ohm)
or, R' = 90 ohm.
Answered by
2
answer:
The total volume of wire remains the same.
l - previous length
l' - new length= 3l
A- previous area
A'=new area.
l*A=l'*A'. (As volume is constant)
or, l *A= 3l*A
or, A'=A/3
R = k*(l/A). (k is the resistivity)
R'(new resistance) = k*(l'/A').
Dividing the two equations,
R'/R= (l'/A')*(A/l)
A= A'/3
l' = 3l
R' : R = (3l/A)*(A/l)
R' = 90 ohm.
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