Q.

The radius (r), length (l) and resistance (R) of a metal wire was measured in the laboratory as                              [2024]

 

r=(0.35±0.05)cm

 

R=(100±10)ohm

 

l=(15±0.2)cm

 

The percentage error in resistivity of the material of the wire is

1 25.6%  
2 39.9%  
3 37.3%  
4 35.6%  

Ans.

(2) 

        ρρ=RR+2rr+ll

        =10100+2×0.050.35+0.215

         =110+27+175

          ρρ=39.9%