Concept explainers
A 2.0-m length of wire is made by welding the end of a 120-cm-long silver wire to the end of an 80-cm-long copper wire. Each piece of wire is 0.60 mm in diameter. The wire is at room temperature, so the resistivities are as given in Table 25.1. A potential difference of 9.0 V is maintained between the ends of the 2.0-m composite wire. What is (a) the current in the copper section; (b) the current in the silver section: (c) the magnitude of
Want to see the full answer?
Check out a sample textbook solutionChapter 25 Solutions
University Physics with Modern Physics, Volume 1 (Chs. 1-20) and Mastering Physics with Pearson eText & ValuePack Access Card (14th Edition)
Additional Science Textbook Solutions
College Physics
The Cosmic Perspective (8th Edition)
Conceptual Physics (12th Edition)
College Physics
Tutorials in Introductory Physics
- Most of the resistance of the human body comes from the skin, as the interior of the body contains aqueous solutions that are good electrical conductors. For dry skin, the resistance between a person’s hands is typically 510 kiloohm. The skin is on average about 2.00 mm thick. We can model the body between the hands as a cylinder 1.60 m long and 12.0 cm in diameter with the skin wrapped around it. What is the resistivity of the skin?arrow_forwardA gold wire 2 mm in diameter and 100 m long is heated to 300°C. Note: p. = 2.44 x 10 -8 Q-m @ 20° C, a = 3.4 x 10 3 / °C @ 20° C %3D %3D What is the resistivity of the gold wire at 300°C? O 4.76 x 10-8Q-m O 2.44 x 1080-m O 2.32 x 10-8Q-m O 4.93 x 108 2-marrow_forwardCopper has a work function of 4.70 eV, a resistivity of 1.7 x10-8 Ω ∙ m, and a temperature coefficient of 3.9 x10 -3 °C -1. Suppose you have a cylindrical wire of length 1.5 m and diameter 0.40 cm connected to a variable power source.a) Draw a clear physics diagram b) At what temperature would the wire have 2 times the resistance that it has at 20 °C?c) What is the peak wavelength of radiation emitted by a wire of thistemperature?d) If light at only the wavelength found above were shone onto a copper plate, what would be the maximum kinetic energy of the ejected electrons?arrow_forward
- The resistance of a very fine aluminum wire with a 13 μm × 13 μm square cross section is 700 Ω . A 700 Ω resistor is made by wrapping this wire in a spiral around a 3.3-mm-diameter glass core. How many turns of wire are needed?arrow_forwardAs 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 0.893 Ω. The resistivity of copper is 1.72 10-8 Ω · m and its density is 8.92 103 kg/m3. What length of wire do you end up with? What is the diameter of the wire?arrow_forwardWire C and wire D are made from different materials and have length Lc = Lp = 2.6 m. The resistivity and diameter of wire C are 5.4 x 10-6 Q-m and 1.30 mm, and those of wire D are 2.9 x 10-6 Q-m and 0.60 mm. The wires are joined as shown in the figure and a current of 3.7 A is set up in them. What is the electric potential difference between (a) points 1 and 2 and (b) points 2 and 3? What is the rate at which energy is dissipated between (c) points 1 and 2 and (d) points 2 and 3? D Lp 1 3. (a) Number i Units V (b) Number i Units (c) Number i Units (d) Number i Unitsarrow_forward
- A tungsten wire has a radius of 0.093 mm and is heated from 20.0 to 1322 °C. The temperature coefficient of resistivity is a = 4.5 x 10 3 (Cº)-¹. When 110 V is applied across the ends of the hot wire, a current of 2.3 A is produced. How long is the wire? Neglect any effects due to thermal expansion of the wire. Number i 4.408939318 Units marrow_forwardWire C and wire D are made from different materials and have length LC = LD = 3.6 m. The resistivity and diameter of wire C are 4.8 × 10-6 Ω·m and 1.06 mm, and those of wire D are 4.0 × 10-6 Ω·m and 0.73 mm. The wires are joined as shown in the figure and a current of 4.3 A is set up in them. What is the electric potential difference between (a) points 1 and 2 and (b) points 2 and 3?arrow_forwardA copper wire is r = 2.19 cm in radius and 2.6 m in length, has a resistivity of 1.72x10^-8 Ω m, and carries a current of 3.23 A. The wire has a charge carrier density of 8.49x10^28 electrons/m3. What is the electric potential difference, V in volts, across the wire? Note: Express your answer to three significant figures. Use scientific notationarrow_forward
- A 580 mm long tungsten wire, with a 0.048 mm diameter circular cross section, is wrapped around in the shape of a coil and used as a filament in an incandescent light bulb. When the light bulb is connected to a battery, a current of 0.536 A is measured through the filament. Tungsten has a resistivity of 4.9 x 10-8 Ohms x m. How many electrons pass through this filament in 5 seconds? What is the resistance of this filament? What is the voltage of the battery that would produce this current in the filament?arrow_forwardA wire is 100.0 m long and 0.800 mm in diameter. The first x meters of the wire is made of copper and the rest of the wire is made of tungsten. When a 10.0 V potential difference is applied across the ends of the wire in a 20.0°C environment, a current of 1.16 A is observed. a) How much of the wire is made of copper? x = ______________________________ b) If the apparatus is moved to a 0.0°C environment, would you expect the current to increase, decrease, or remain constant? Explain your answer, including a description of what is going on inside the wire at a microscopic level. c) If the apparatus is moved to a 125°C environment, how much power will be dissipated by the wire? Explain what that means (what forms of energy are involved, what is the rate of energy transformation) P = ______________________________arrow_forwardA tungsten wire has a radius of 0.085 mm and is heated from 20.0 to 1344 °C. The temperature coefficient of resistivity is a = 4.5 x 10 3 (C°) 1. When 100 V is applied across the ends of the hot wire, a current of 1.3 A is produced. How long is the wire? Neglect any effects due to thermal expansion of the wire. Number Unitsarrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning