Question

A wire has length 80 cm has resistance 10 ohm . find the resistance of the wire of the same material and of same sectional area but of length 1.2m.​

Answer 1

Answer:

15ohm

Step-by-step explanation:

resistivity will be always same....

so ,

R1A/L1=R2A/L2

10/0.8=R2/1.2   {Area of cross section remains unchanged..and it gets cancled.

                          80cm=0.8m}

R2=15ohm {after calculating}

Answer 2

Answer:

15 Ω

Step-by-step explanation:

Let we have two wire :  

Length of first wire is 80 cm or 0.8 m

Length of second wire is 1.2 m

Resistance of 10 Ω in first wire .

We have find resistance in second wire .

We have :

p  = R × A / L

For first wire :

p = 10 × A / 0.8

For second wire :

p' = R × A' / 1.2

Same material [ i.e. p = p' ] & same cross section are [ i.e. A = A' ]

10 × A / 0.8 = R × A / 1.2

10 / 0.8 = R / 1.2

R = 12 / 0.8

R = 15 Ω

Hence the resistance of the wire is 15 Ω