Question

Assertion : If a wire is stretched such that its area is halved, its resistance would become 4 times.
Reason: The data is insufficient to predict.​

Answer 1

Answer:

Explanation:

both, Assertion and Reason are true and the reason is correct explanation of the Assertion

According to the question, wire is  

stretched 3 times to its original length  

Volume of wire is constant, so we get:  

​

 

A  

1

​

L  

1

​

=A  

2

​

L  

2

​

 

A  

1

​

L  

1

​

=A  

2

​

(3L  

1

​

)

A  

2

​

=  

3

A  

1

​

 

​

 

​

 

Since, R=  

A

ρL

​

⇒R  

2

​

=  

A  

1

​

/3

ρ⋅(3L  

1

​

)

​

 

R  

2

​

=9R  

1

​

 

∴ Both assertion & reason is correct.  

​