Physics And Measurement Question 299
Question: The resistance R of a wire is given by the relation $ R=\frac{\rho \ell }{\pi r^{2}} $ . Percentage error in the measurement of $ \rho ,\ell $ and r is 1%, 2% and 3% respectively. Then the percentage error in the measurement of R is
Options:
A) 6
B) 9
C) 8
D) 10
Show Answer
Answer:
Correct Answer: B
Solution:
[b] Given $ R=\frac{\rho \ell }{\pi r^{2}} $ ,then $ \frac{\Delta R}{R}\times 100 $
$ =\frac{\Delta \rho }{\rho }\times 100+\frac{\Delta \ell }{\ell }\times 100+2\frac{\Delta r}{r}\times 100 $
$ =1%+2%+2\times 3%=9% $
