Question

a nichrome wire of resistance 18 ohm triple on it . calculate its resistance of the wire​

Answer 1

Answer: Let length of wire =1, Area of coress section =A=πr  

2

 ( where r= radius of wire)

Then  Resistance, R=ρ  

A

1

​  

=ρ  

πr  

2

 

1

​  

→(1)

When radius becomes  

2

r

​  

 then volume would still be same so :  

V  

1

​  

=V  

2

​  

 

⇒πr  

2

l=π(  

2

r

​  

)  

2

l  

2

​  

 (where l  

2

​  

= new length)

⇒l  

2

​  

=4l

So the new resistance R  

new

​  

=ρ  

A  

2

​  

 

l  

2

​  

 

​  

=ρ  

πr  

2

 

4l

​  

×4=16R

But R=18Ω ( given)

⇒R  

new

​  

=16×18=288Ω

Answer 2

Answer:

I think 2ohm

Explanation:

hope it's help

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