1.

a wire of given material having length and area of cross section a has a resistance of 6 ohm what would be the resistance of another wire of the same material having length 2L and area of cross section a/2​

Answer»

ANSWER:

Now the resistance of a wire can be expressed as:

R=ρ

A

l

Where RESISTIVITY is ρ.

Now a second wire is twice as long and of half cross section.

Let final length be l

1

, DIAMETER be d

1

and

cross section Area be A

1

.

A

1

=

2

A

R

1

=ρ

A

1

l

1

Putting the VALUE of l

1

=2l and A

1

=

2

A

We have, resistance of the new second wire, R

2

=ρ

A

4l

=4×R

1

=4×8=32Ω


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