BackFor some applications, it is important that the value of a resistance not change with temperature. For example, suppose you made a 3.60-k Ω resistor from a carbon resistor and a Nichrome wire-wound resistor connected together so the total resistance is the sum of their separate resistances. What value should each of these resistors have (at 0°C) so that the combination is temperature independent?
Compute the voltage drop along an 18-m length of household no. 14 copper wire (used in 15-A circuits). The wire has diameter 1.628 mm and carries a 12-A current.
Two aluminum wires have the same resistance. If one has twice the length of the other, what is the ratio of the diameter of the longer wire to the diameter of the shorter wire?
Can a 1.8-mm-diameter copper wire have the same resistance as a tungsten wire of the same length? Give numerical details.
What is the resistance of a 5.1-m length of copper wire 1.5 mm in diameter?
(II) A bird stands on a dc electric transmission line carrying 3800 A (Fig. 25–35). The line has 2.5 x 10-5Ω resistance per meter, and the bird’s feet are 4.0 cm apart. What is the potential difference between the bird’s feet?
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(II) A rectangular solid made of carbon has sides of lengths 1.0 cm, 2.0 cm, and 4.0 cm, lying along the x, y, and z axes, respectively (Fig. 25–36). Determine the resistance for current that passes through the solid in the x direction (Assume the resistivity is ρ = 3.0 x 10-5 Ω m).
A rectangular solid made of carbon has sides of lengths 1.0 cm, 2.0 cm, and 4.0 cm, lying along the x, y, and z axes, respectively (Fig. 25–36). Determine the resistance for current that passes through the solid in the y direction, (Assume the resistivity is ρ = 3.0 x 10⁻⁵ Ω•m).
A rectangular solid made of carbon has sides of lengths 1.0 cm, 2.0 cm, and 4.0 cm, lying along the x, y, and z axes, respectively (Fig. 25–36). Determine the resistance for current that passes through the solid in the z direction. (Assume the resistivity is ρ = 3.0 x 10-5 Ω•m) .
Eight identical bulbs are connected in series across a 120-V line. What is the voltage across each bulb?
Calculate the terminal voltage for a battery with an internal resistance of 0.900 Ω and an emf of 6.00 V when the battery is connected in series with a 610-Ω resistor.
A galvanometer has an internal resistance of 32 Ω and deflects full scale for a 48-μA current. Describe how to use this galvanometer to make an ammeter to read currents up to 25 A.
Calculate the terminal voltage for a battery with an internal resistance of 0.900 Ω and an emf of 6.00 V when the battery is connected in series with a 61.0-Ω resistor.
Neglect the internal resistance of a battery unless the problem refers to it. Ten 7.0-W Christmas tree lights are connected in series to each other and to a 120-V source. What is the resistance of each bulb?
Neglect the internal resistance of a battery unless the problem refers to it. Eight bulbs are connected in parallel to a 120-V source by two long leads of total resistance 1.4 Ω. If 210 mA flows through each bulb, what is the resistance of each, and what fraction of the total power is wasted in the leads?