Question

a wire of resistivity r is stretched to double its length. how does it affect the (a) resistance (b) resistivity

Answer 1

a)resistance will became doubled because it is directly proportional to r
b)resistivity will remain same

Answer 2

 (a) resistance 
---------------------------------
 resistance  is directly proportional to the length of the wore so it will also double 

------------------------------------------------------------------------------------
 (b) resistivity 
-----------------------------
resistivity  only depends of nature and temperature of the conductor hence resistivity  will not change , will remain the same