Grade 12th passAIPMT

a uniform wire of resistance of 20ohm having resistance 1 ohm/m is bent to form circle. if the equivalent resistance is 1.8ohm the length of shorter is what.

Question image for a uniform wire of resistance of 20ohm having resis

Parul Rajput

9 Years agoGrade 12th pass

2 Answers

nigamananda mishra

8 Years ago

Let there be two resistance between pq one from above and 1 from below....

let R₁ be the resistance from below.....the R₂=20-R_{1 ….}

Now R_eq=R₁ x R₂/R₁+ R₂

= (20-R₁)R₁=1.8(R₁+R₂)

Solving the quadratic we get R1= 2 or 18

As R1 is smaller resistance …. R1 = 2

As resistance = 1 ohm/ metre

Therefore,distance between p and q = 2m

If you have any queries please ask

Rishi Sharma

5 Years ago

Dear Student,
Please find below the solution to your problem.

Let there be two resistance between pqone from above and 1 from below....
let R1 be the resistance from below.....the R2=20-R1 ….
Now Req=R1x R2/R1+ R2
= (20-R1)R1=1.8(R1+R2)

Solving the quadratic we get R1= 2 or 18
As R1 is smaller resistance …. R1 = 2
As resistance = 1 ohm/ metre
Therefore,distance between p and q = 2m

Thanks and Regards