. Specific resistance p of a thin circular wire of
radius r сm, resistance R ohms and length L is
given by p = nr^2 R/L. If r = 0.26 +/_0.01 cm, R =
30 +/_ 2 ohm and L = 75.00 +/_ 0.01 cm, find the
percentage error in p.
Answers
Answered by
1
Explanation:
The specific resistance is given as :
ρ=
l
πr
2
R
Differentiating both sides given (in terms of relative error ):-
ρ
ΔP
=2
r
Δr
+
R
ΔR
+
l
Δl
→(2)
From given data,
r=0.24±0.02cm⇒
r
Δr
=
0.24
0.02
=
12
1
R=30±1Ω⇒
R
ΔR
=
30
1
l=4.80±0.01cm⇒
L
ΔL
=
4.80
0.07
=
480
1
Hence from (1),
ρ
ΔP
=2×
12
1
+
30
1
+
480
1
=20.2%
December 27, 2019
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