Answer:
[tex]i = 7.438\,A[/tex]
Explanation:
Current can be determined by Ohm's Law, whose expression is:
[tex]i = \frac{V}{R}[/tex]
Where [tex]R[/tex] is the electrical resistance, whose formula is described below:
[tex]R = \frac{\rho\cdot L}{A_{t}}[/tex]
Where [tex]\rho[/tex], [tex]L[/tex] and [tex]A_{t}[/tex] are the electrical resistivity and wire length and cross area, respectively. The electrical resistivity for tungsten is [tex]5.65\times 10^{-8}\,\Omega \cdot m[/tex]. Finally, the electrical resistance is computed herein:
[tex]R =\frac{(5.65\times 10^{-8}\,\Omega\cdot m)\cdot (1.50\,m)}{0.7\times 10^{-6}\,m^{2}}[/tex]
[tex]R = 0.121\,\Omega[/tex]
Moreover, the current in the wire is:
[tex]i = \frac{0.9\,V}{0.121\,\Omega}[/tex]
[tex]i = 7.438\,A[/tex]
Answer:
7.5 A.
Explanation:
From Ohm's Law,
V = IR............................. Equation 1
Where V = Voltage, I = current, R = Resistance.
make I the subject of the equation
I = V/R..................... Equation 2
Recall That,
R = ρL/A..................... Equation 3
Where ρ = Resistivity of tungsten wire, L = Length of the wire, A = cross sectional area of tungsten wire.
Substitute equation 3 into equation 2
I = V/(ρL/A)
I = VA/ρL.................... Equation 4
Given: V = 0.9 V, A = 0.7 mm² = (0.7/1000000) m² = 7.0×10⁻⁷ m², L = 1.5 m
Constant: 5.60×10⁻⁸ Ωm
Substitute into equation 4
I = 0.9(7.0×10⁻⁷)/(5.60×10⁻⁸ ×1.5)
I = 7.5 A.
