A long metallic wire is stretched along the x direction. The applied potential difference along

the wire is 12 volts. The resistance of the wire is estimated to be 8 Ohm.

a. Calculate the current in the wire and the passing charge in 2 seconds.

b. Calculate the electric power dissipated in the wire.

This wire has a length of 100 m and the material of the wire has a resistivity of 1.6 x 10 - 8 Ωm.

c. Calculate the cross-section area of the wire.

d. Calculate the conductivity of the wire.

e. What is the capacitance of the capacitor, that is connected to a series resistor of 8 MΩ in an RC

circuit that has a time constant of one second.

Question

Physics

Jerome Jackson

22 February, 11:51

A long metallic wire is stretched along the x direction. The applied potential difference along

the wire is 12 volts. The resistance of the wire is estimated to be 8 Ohm.

a. Calculate the current in the wire and the passing charge in 2 seconds.

b. Calculate the electric power dissipated in the wire.

This wire has a length of 100 m and the material of the wire has a resistivity of 1.6 x 10 - 8 Ωm.

c. Calculate the cross-section area of the wire.

d. Calculate the conductivity of the wire.

e. What is the capacitance of the capacitor, that is connected to a series resistor of 8 MΩ in an RC

circuit that has a time constant of one second.

+4

Answers (1)

Know the Answer?

Denzel Douglas · Answer 1

a) I = 1.5 A, b) P = 18 W, c) A = 8 10⁻⁷ m², d) σ = 0.625 10⁸ (Ω m) ⁻¹,

e) C = 0.125 10⁻⁶ F

Explanation:

a) for this exercise let's use Ohm's Law

V = I R

I = V / R

I = 12/8

I = 1.5 A

b) the power is given by the expression

P = V I

P = V V / R = V² / R

P = 12²/8

P = 18 W

c) the resistance of the wire is given by

R = ρ l / A

A = ρ l / R

A = 1.6 10⁻⁸ 100/8

A = 8 10⁻⁷ m²

d) conductivity is the inverse of resistivity

σ = 1 / ρ

σ = 1 / 1,610⁻⁸

σ = 0.625 10⁸ (Ω m) ⁻¹

e) In an RC circuit the response time is

τ = RC

C = τ / R

C = 1/8 10⁶

C = 0.125 10⁻⁶ F