Calculate the resistance of 915 meters length of a wire having a uniform cross-sectional area of 0.77 cm^2 if the wire is made of copper having a resistivity of 1.7 × 10^(–6) Ω - cm. *
Answers
Answered by
1
Explanation:
In the question, it is given that the resistance of one meter wire is 3 ohms. So the resistance of 1.5 meters of the same wire is given as
1
3×5
=15ohms.
The resistance of a resistor is given by the formula R=ρ
A
L
where ρ is the resistivity of the material the resistor is made of, l is the length of the resistor and A is the cross-sectional area.
Let the resistance of the wire is initially equal to R. R=ρ
A
L
.
When the area of cross-section of the wire is doubled and so the resistance of the wire is given as R
′
=ρ
2(A)
L
.
The new resistance is R
′
=
2
R
.
Hence, the changed resistance of the wire is 15/2=7.5 ohms.
Similar questions