Question

A wire of given material having length L and area of cross section A has a resistance of 2
ohm. a) Find the resistance of another wire of same material having length 2L and area of
cross section A/2​

Answer 1

Answer:

व्हाट इस योर क्वेश्चन

उइझुइझ्हिज्ब्ब्

Answer 2

Answer:

Wire of uniform cross-section has a resistance of R. Let the diameter be d,  the length of the wire be l cross-sectional area be A.

Now the resistance of a wire can be expressed as:

R=ρAl​

Where resistivity is ρ.

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

Let final length be l1​, diameter be d1​ and

cross section Area be A1​.

A1​=2A​

R1​=ρA1​l1​​

Putting the value of l1​=2l and A1​=2A​

We have, resistance of the new second wire, R2​=ρA4l​=4×R1​=4×8=32Ω

Explanation: