Question

1) TWO copper wires A and B oflength 30 M and 10 M have radii 2CM and ICM respectively
Compare the resistance of two wires.
(3)​

Answer 1

Answer:   As both the wires are of same material, therefore their resistivity will be same.

Now, the length of wire A= 30m=L

Radius of wire A=2cm=0.02m

Area of wire=pie*r*r=A

Area of wire A=pie*0.02r*0.02r

= 0.0004r*square pie

=0.0004A

Reaistance of a wire=resistivity*L/A =R

Resistance of wire A= 30L/0.0004A=7500R

Similarly, resistivity of wireB=10L/0.0001A=10000R

So resistance of wire B is more than wire A