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- Explain why R=R0(1 + a?T) for the temperature variation of the resistance R of an object is not as accurate as P=P0(1 + a?T) which gives the temperature variation of resistivity P.arrow_forwardA spool of iron wire 260 m long and with a diameter of 0.320 mm is at 20.0°C. For iron, the resistivity is 10.0 ✕ 10−8 Ω · m and the temperature coefficient of resistivity is 5.00 ✕ 10−3 (°C)−1. (a) What is the magnitude of the electric field (in V/m) in the wire if it carries a current of 0.550 A? V/m (b) What is the electric power (in W) delivered to the spool while it carries a current of 0.550 A? W (c) What is the power (in W) delivered to the spool if the potential difference across the wire is held constant and the temperature is increased to 280°C? Warrow_forwardA straight, cylindrical wire lying along the x axis has a length of 0.515 m and a diameter of 0.195 mm. It is made of a material described by Ohm's law with a resistivity of ? = 4.00 ✕ 10−8 Ω · m. Assume a potential of 4.00 V is maintained at the left end of the wire at x = 0. Also assume V = 0 at x = 0.515 m. (a) Find the magnitude (in V/m) and direction of the electric field in the wire. (b) Find the resistance of the wire (in Ω). (c) Find the magnitude (in A) and direction of the electric current in the wire. (d) Find the current density in the wire (in MA/m2). See image for the full question.arrow_forward
- A 1.30 m cylindrical rod of diameter 0.500 cm is connected to a power supply that maintains a constant potential difference of 15.0 V across its ends, while an ammeter measures the current through it. You observe that at room temperature (20.0∘C) the ammeter reads 18.8 A, while at 92.0∘C it reads 16.6 A. You can ignore any thermal expansion of the rod. (A) Find the resistivity for the material of the rod at 20∘C Express your answer with the appropriate units. (B) Find the temperature coefficient of resistivity at 20∘C for the material of the rod. Express your answer in inverse degrees Celsius.arrow_forwardA spool of iron wire 320 m long and with a diameter of 0.360 mm is at 20.0°C. For iron, the resistivity is 10.0 ✕ 10−8 Ω · m and the temperature coefficient of resistivity is 5.00 ✕ 10−3 (°C)−1. (a)What is the magnitude of the electric field (in V/m) in the wire if it carries a current of 0.550 A?V/m (b)What is the electric power (in W) delivered to the spool while it carries a current of 0.550 A? W (c)What is the power (in W) delivered to the spool if the potential difference across the wire is held constant and the temperature is increased to 310°C? Warrow_forwardA cylindrical resistor of radius 3.0 mm and a length of 3.0 cm has a resistivity of 2.6 x 10-3 Ωm. If this resistor is hooked up to a 9.0-volt battery, what will be the resultant current in the wire? a. 1.7 A b. 3.3 A c. 4.0 A d. 2.6 A e. 1.1 Aarrow_forward
- Two conductors are made of the same material and have the same length. Conductor 1 is asolid wire of diameter 2.0 m. Conductor 2 is a hollow tube of outside diameter 3.0 m andinside diameter 2.0 m. The ratio of their resistance, R1/R2, is: CHOICES: 1.5/4.3/2.3.8. Which of the following wires has the least resistance? (Assume that they have the sameresistivity.) Choices: Thin, long, and hot.Thin, short, and hot.Thin, short, and cool.Thick, long, and hot.arrow_forwardYou are holding four wires made of the same material, but of varying sizes. Which of these wires would have the lowest resistance? A. 1 cm long, 1 cm radiusB. 2 cm long, 1 cm radiusC. 0.5 cm long, 1 cm radius D. 1 cm long, 0.5 cm radiusarrow_forwardA straight, cylindrical wire lying along the x axis has a length of 0.5 m and a diameter of0.2 mm. It is made of a material described by Ohm’s law with a resistivity of ρ 4 × 10-8Ωm. Assume a potential of 4 V is maintained at the left end of the wire at x = 0. Alsoassume V = 0 at x = 0.5 m. Find (a) the magnitude and direction of the electric field in thewire, (b) the resistance of the wire, (c) the magnitude and direction of the electric currentin the wire, and (d) the current density in the wire. (e) Show that E = ρ J. (E = −dVdx)arrow_forward
- You have a 100 meter long hollow square copper wire that has a side length of 5mm. The diameter of the cylindrical interior is 3.5 mm. If copper had a resistivity of (1.7x10^(-8)Ωm, what is the resistance of the wire? The units for the options are Ω. a.0.022 b. 0.068 c.0.11 d. 0.18 E.0.24arrow_forwardAt room temperature, what is the strength of the electric field in a 12 gauge copper wire (diameter 2.05 mm) that is needed to cause a 3.90 A current to flow? Use the resistivity at room temperature for copper ρ = 1.72×10−8 Ω⋅m. Express your answer with the appropriate units. What field would be needed if the wire were made of silver instead? Use the resistivity at room temperature for silver ρ = 1.47×10−8 Ω⋅m. Express your answer with the appropriate units.arrow_forwardKiting during a storm. The legend that Benjamin Franklin flew a kite as a storm approached is only a legend — he was neither stupid nor suicidal. Suppose a kite string of radius 2.10 mm extends directly upward by 0.802 km and is coated with a 0.520 mm layer of water having resistivity 155 Ω·m. If the potential difference between the two ends of the string is 176 MV, what is the current through the water layer? The danger is not this current but the chance that the string draws a lightning strike, which can have a current as large as 500 000 A (way beyond just being lethal).arrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax College