The radius (r), length (l) and resistance (R) of a metal wire was measured in the laboratory as 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 :
- 37.3\%
- 25.6\%
- 35.6\%
- 39.9\%
Answer
(4) 39.9\%
Solution
= RAl= R r2l
= RR+2 rr+ ll
= 10100+2 0.050.35+ 0.215
=0.100+0.286+0.013=0.399
percentage error =39.9\%
Answer: (4)