Question

the resistance of a conducting wire x of length one metre is 5 ohm calculate the resistance of the wire made by the same material whose length is 4 times and area of cross section is five times that of wire x(at same temperature)​

Answer 1

Answer:

4x/25

Explanation:

resistance dirctly propotional to length and invesrsly to area

Answer 2

Answer:

The resistance of new wire is $4\ \Omega.$

Explanation:

Given :

Length of wire x = 1 m.

Resistance , $R=5 \ \Omega.$

We know, $R=\dfrac{\rho \ L}{A}$

( Here $\rho$ is specific resistance depend on material property . It is independent of shape and size)

Now, when length is 4 times and area is 5 times .

Therefore, $R'=\dfrac{\rho (4L)}{(5A)}=\dfrac{4}{5}\dfrac{\rho L}{A}=\dfrac{4}{5}R=4\ \Omega.$

The resistance of new wire is $4\ \Omega.$

Hence, this is the required solution.