a) increase by 0.05%
b) increase by 0.2%
c) decrease by 0.2%
d) decrease by 0.05%
Doubt by Veer
Text Solution :
We know,
R = ρL/A
R = ρL/A
L'=L+0.1% of L
L'=L+0.001L
L'=1.001L
Volume of the wire, V=LA=L'A'
A'=LA/L'
A'=LA/1.001L
A'=A/1.001
R'=ρL'/A'
R'=ρ(1.001L)/[A/1.001]
R'=(ρL/A)(1.001)²
R'=R(1.001)²
R'=R(1.002001)
Percentage Increase in Resistance of the wire
=[(R'-R)/R]×100
= [R(1.002001)-R]/R ×100
=0.002001×100
=0.2001%
≈0.2%
The correct answer is b) increases by 0.2%
L'=L+0.001L
L'=1.001L
Volume of the wire, V=LA=L'A'
A'=LA/L'
A'=LA/1.001L
A'=A/1.001
R'=ρL'/A'
R'=ρ(1.001L)/[A/1.001]
R'=(ρL/A)(1.001)²
R'=R(1.001)²
R'=R(1.002001)
Percentage Increase in Resistance of the wire
=[(R'-R)/R]×100
= [R(1.002001)-R]/R ×100
=0.002001×100
=0.2001%
≈0.2%
The correct answer is b) increases by 0.2%
Video Solution :
