Wires A and B, having equal lengths of 42.6 m and equal diameters of 2.87 mm, are connected in series. A potential difference of 63.3 V is applied between the ends of the composite wire. The resistances are RA = 0.111 Q and Rg = 0.637 Q. For wire A, what are (a) magnitude J of the current density and (b) potential difference V? (c) Of what type material is wire A made (see the table below)? For wire B, what are (d) J and (e) V? (f) Of what type material is B made? Resistivities of Some Materials at Room Temperature (20°C) Resistivity, p (N-m) Material Silver Copper Gold Aluminum Manganin Tungsten Iron Platinum Silicon, pure Silicon, n-type Silicon,p-type Glass Fused quartz Typical Metals 1.62 x 10-8 1.69 x 10-8 2.35 x 10-8 2.75 X 10-8 4.82 x 10-8 5.25 x 10-8 9.68 x 10-8 10.6 × 10-8 Typical Semiconductors 2.5 × 10³ 8.7 x 10-4 2.8 x 10-3 Typical Insulators 10101014 -1016 Temperature Coefficient of Resistivity, a (K-¹) 4.1 x 10-3 4.3 × 10-3 4.0 × 10-3 4.4 x 10-3 0.002 × 10-3 4.5 x 10-3 6.5 x 10-3 3.9 x 10-3 -70 × 10-³ "An alloy specifically designed to have a small value of a. *Pure silicon doped with phosphorus impurities to a charge carrier density of 10²3 m³. "Pure silicon doped with aluminum impurities to a charge carrier density of 102³ m-³.

A copper wire of radius a = 0.240 mm has an aluminum jacket of outer radius b = 0.329 mm. There is a current i = 1.57 A in the composite wire. Take the resistivity for copper and aluminum to be 1.69 × 10-8Ω·m and 2.75 × 10-8Ω·m. Calculate the current in (a) the copper and (b) the aluminum. (c) If a potential difference V = 13.1 V between the ends maintains the current, what is the length in meters of the composite wire?

A lightning rod on top of a building consists of an iron spike 1.5 m long with a circular crosssection of diameter 1.5 cm. During a lightning strike, the rod carries a current of 1000 A. What is the potential difference across the rod when this current flows? The resistivity of iron is 1.0 x 10-7 Ωm.

An aluminum wire having a cross-sectional area equal to 3.10 x 10-6 m² carries a current of 6.00 A. The density of aluminum is 2.70 g/cm³. Assume each aluminum atom supplies one conduction electron per atom. Find the drift speed of the electrons in the wire. The equation for the drift velocity includes the number of charge carriers per volume, which in this case is equal to the number of atoms per volume. How do you calculate that if you know the density and the atomic weight of aluminum? mm/s

A wire 3.43 m long and 6.38 mm in diameter has a resistance of 11.6 mQ. A potential difference of 17.7 V is applied between the ends. (a) What is the current in amperes in the wire? (b) What is the magnitude of the current density? (c) Calculate the resistivity of the material of which the wire is made. (a) Number Units (b) Number i Units (c) Number i Units >

As part of a class project you are given 0.900 g of copper and asked to fabricate a wire with uniform cross-section. You use up 95% of the copper and make a wire with a resistance of 0.723 Ω. The resistivity of copper is 1.72  10-8 Ω · m and its density is 8.92  103 kg/m3. (a) What length of wire do you end up with? (m)(b) What is the diameter of the wire? (mm)

Electric current passing through a human body can be dangerous, even fatal, depending on the amount of current, the duration of the current, and the region of the body through which the current passes. However, currents less than about 0.5 mA are typically imperceptible. A current caused by a low potential difference typically travels through the outer layer of the skin. The resistance of the skin therefore determines how much current flows for a given potential difference. The resistance can be influenced by a number of factors, including whether the skin is wet or dry . For example, suppose an electric current of 89.0 µA follows a path through the thumb and index finger. When the skin is dry, the resistance along this path is 4.40 ✕ 105 Ω. What voltage (in V) is required for this current, in the case of dry skin? V When the skin is wet, the resistance is lowered to 1,950 Ω. What voltage (in V) is required for the same current, in the case of wet skin? V

Wires A and B, having equal lengths of 41.8 m and equal diameters of 2.89 mm, are connected in series. A potential difference of 61.6 V is applied between the ends of the composite wire. The resistances are RA = 0.108 0 and Rg - 0.617 0. For wire A, what are (a) magnitude Jof the current density and (b) potential difference V? (c) Of what type material is wire A made (see the table below)? For wire B. what are (d) Jand (e) V? (f) Of what type material is B made? Resistivities of Some Materials at Room Temperature (20°C) Resistivity, p (N-m) Temperature Coefficient of Resistivity, a (K) Material Typical Metals 4.1 x 10- 1.62 x 10- 1.69 x 10- Silver 4.3 x 10- Copper Gold 4.0 x 10- 4.4 x 10- 0.002 x 10- 45 x 10- 6.5 x 10- 2.35 x 10 2.75 x 10- 4.82 x 10- 5.25 x 10- 9.68 x 10- 10.6 x 10- Aluminum Manganin Tungsten Iron Platinum 3.9 x 10- Typical Semiconductors 25 x 10 8,7 x 10- -70 x 10- Silicon, pure Silicon, n-type Silicon, p-type 2.8 x 10- Typical Insulators 10- 104 ~10M Glass Fused…