Question

If a resistance if a conductor of length 5m is 10 ohm .what will be the resistance of a conductor of length 20m of the same material

Answer 1

✤✤✤✤✤✤✤Question✤✤✤✤✤✤✤

If a resistance of a conductor of length 5 m is 10 ohm. what will be the resistance of a conductor of length 20 m of the same material.

✤✤✤✤✤✤✤Solution✤✤✤✤✤✤✤

Resistance of conductor, R = 10 ohm

length of conductor, l = 5 m

resistivity of conductor = p (constant)

area of cross section = A

Now,

as we know

$\mathtt{resistance = p\times \frac{l}{A\: } }$

so,

$10 = p \times \frac{5}{A} \\ \\ A= \frac{5p}{10} \\ \\ A = \frac{p}{2}$

Now,

we have to find the resistance of conductor when its length is 20 m

so,

$\mathtt{resistance = p\times \frac{l}{A} }$

$R \: = p \times \frac{20}{A} \\ \\ R = p \times \frac{20}{ \frac{p}{2} } \\ \\ R = 40 \: ohms$

Hence the new resistance will be 40 ohms.

Answer 2

Answer:

If a resistance of a conductor of length 5 m is 10 ohm. what will be the resistance of a conductor of length 20 m of the same material.

✤✤✤✤✤✤✤Solution✤✤✤✤✤✤✤

Resistance of conductor, R = 10 ohm

length of conductor, l = 5 m

resistivity of conductor = p (constant)

area of cross section = A

Now,

as we know

\mathtt{resistance = p\times \frac{l}{A\: } }resistance=p×

A

l

so,

\begin{lgathered}10 = p \times \frac{5}{A} \\ \\ A= \frac{5p}{10} \\ \\ A = \frac{p}{2}\end{lgathered}

10=p×

A

5

A=

10

5p

A=

2

p

Now,

we have to find the resistance of conductor when its length is 20 m

so,

\mathtt{resistance = p\times \frac{l}{A} }resistance=p×

A

l

\begin{lgathered}R \: = p \times \frac{20}{A} \\ \\ R = p \times \frac{20}{ \frac{p}{2} } \\ \\ R = 40 \: ohms\end{lgathered}

R=p×

A

20

R=p×

2

p

20

R=40ohms