In the figure shown below, you see a cross section of a weird coaxial cable. The regions in the figure are described as Region I: A steel wire of radius a = 10.0000 cm, with a current density of J = J₁r, where J₁ =12.0000 in the appropriate units. Region II: A section of insulating material with an outer radius b = 20.0000 cm. Region III: A cylindrical shell of steel outer radius c = 30.0000 cm with a current density of JIII J3=8.0000 in the appropriate units. The current density JIII moves in the opposite direction of Jr. where Region IV: The air outside the coaxial cable. C 10 I II III IV The magnitude of the magnetic field at r = 35.0000 cm is, in nT and to two decimal places, (1 nT=1 x 10⁹T)

A conducting rod with a circular cross-section (this rod is a cylinder) has a radius of 1o mm and is 2 metres long. The rod is made of aluminum, so its conductivity is 3.6 x 10' s/m. A potential difference (voltage) is applied at both ends of this rod and the current is I= 90 A. That's a lot of current! a. What is the resistance of the rod, when measured from one end to the other? b. Calculate the current density in the rod along its length. . Determine the electric field amplitude at all locations within the rod. d. What is the electric potential difference between the two ends of the rod.

The figure below represents a section of a circular conductor of nonuniform diameter carrying a current of I = 4.50 A. The radius of cross-section A, is r, = 0.450 cm. A1 (a) What is the magnitude of the current density across A,? |A/m² The radius r, at A, is larger than the radius r, at A,. (b) Is the current at A, larger, smaller, or the same? O The current is larger. O The current is smaller. O The current is the same. (c) Is the current density at A, larger, smaller, or the same? O The current density is larger. O The current density is smaller. O The current density is the same. Assume A, = 2A1 (d) Specify the radius at A2. mm (e) Specify the current at A,. A (f) Specify the current density at A,. A/m2

The quantity of charge q (in coulombs) that has passed through a surface of area 2 cm? varies with time according to the equation q= 2t 3+ 4t - 6, where t is in seconds. What is the value of the current density (A/m²) at t= 6.0 s? 1. O11.0 × 105 2. O 14.9 × 10° 3. O 19.4 × 10° 4. O 24.5 × 10° 5. O30.2 × 105

A 310-km-long high-voltage transmission line 2.00 cm in diameter carries a steady current of 1,030 A. If the conductor is copper with a free charge density of 8.50 x 1028 electrons per cubic meter, how many years does it take one electron to travel the full length of the cable? (Use 3.156 x 107 for the number of seconds in a year.) yr

Consider a wire made of copper with conductivity 6.0 × 10' 2m', which has a circular cross-section of radius 0.47 mm. In a particular circuit, this wire carries a current of 6.5 A. What is the electric field, in volts per meter, inside this wire? E = If we replace this wire with a gold one of the same size, with conductivity 4.1 × 107 2-1'm1, what will the electric field in the wire be? E =

A 340-km-long high-voltage transmission line 2.0 cm in diameter carries a steady current of 1,230 A. If the conductor is copper with a free charge density of 8.5 x 1028 electrons per cubic meter, how many years does it take one electron to travel the full length of the cable? (Use 3.156 × 107 for the number of seconds in a year.) yr

1. Consider a cylindrical wire that has conduction electron density 6.0 × 1028 1 ,3 and radius 0.5 mm. An electric field with strength m- 7.5 × 10-4 creates a current of 4.8 x 10! electrons per second. a) What is the average drift speed for an electron? (include units) b) What is the average time in between electron collisions? fs (express your answer in femtoseconds)

Q.no.7: A beam contains 2.0 × 108doubly charged posi-tive ions per cubic centimeter, all of which are moving north witha speed of 1.0 × 105 m/s. What are the (a) magnitude and (b) direc-tion of the current density J

A 14 gauge copper wire of diameter 1.628 mm carries a current of 10.5 mA. (ρcopper=1.72×10−8Ω⋅m.) a) What is the potential difference across a 2.20 mm length of the wire? Express your answer in volts. b) What would the potential difference in part A be if the wire were silver instead of copper, but all else was the same? ρsilver=1.47×10−8Ω⋅m. Express your answer in volts.