Question: Nichrome wire of cross - sectional radius 0.

> When a driver brakes an automobile, the friction between the brake drums and the brake shoes converts the car’s kinetic energy to thermal energy. If a 1500-kg automobile traveling at 30 m/s comes to a halt, how much does the temperature rise in each of t

> A given copper wire has a resistance of 5.00 Ω at 20.0°C while a tungsten wire of the same diameter has a resistance of 4.75 Ω at 20.0°C. At what temperature will the two wires have the same resistance?

> Consider an aluminum wire of diameter 0.600 mm and length 15.0 m. The resistivity of aluminum at 20.0°C is 2.82 x 1028 Ω · m. (a) Find the resistance of this wire at 20.0°C. (b) If a 9.00 - V battery is connected across the ends of the wire, find the cur

> A car owner forgets to turn off the headlights of his car while it is parked in his garage. If the 12.0 - V battery in his car is rated at 90.0 A · h and each headlight requires 36.0 W of power, how long will it take the battery to completely discharge?

> If a battery is rated at 60.0 A · h, how much total charge can it deliver before it goes “dead”?

> A tungsten wire in a vacuum has length 15.0 cm and radius 1.00 mm. A potential difference is applied across it. (a) What is the resistance of the wire at 293 K? (b) Suppose the wire reaches an equilibrium temperature such that it emits 75.0 W in the form

> A certain laboratory experiment requires an aluminum wire of length of 32.0 m and a resistance of 2.50 Ω at 20.0°C. What diameter wire must be used?

> Two wires A and B made of the same material and having the same lengths are connected across the same voltage source. If the power supplied to wire A is three times the power supplied to wire B, what is the ratio of their diameters?

> An office worker uses an immersion heater to warm 250 g of water in a light, covered, insulated cup from 20.°C to 100.°C in 4.00 minutes. The heater is a Nichrome resistance wire connected to a 120 - V power supply. Assume the wire is at 100.°C throughou

> An electric utility company supplies a customer’s house from the main power lines (120. V) with two copper wires, each of which is 50.0 m long and has a resistance of 0.108 Ω per 300. m. (a) Find the potential difference at the customer’s house for a loa

> The cost of electricity varies widely throughout the United States; $0.120/kWh is a typical value. At this unit price, calculate the cost of (a) Leaving a 40.0 - W porch light on for 2 weeks while you are on vacation, (b) Making a piece of dark toast in

> A student drops two metallic objects into a 120-g steel container holding 150 g of water at 25°C. One object is a 200-g cube of copper that is initially at 85°C, and the other is a chunk of aluminum that is initially at 5.0°C. To the surprise of the stud

> The potential difference across a resting neuron in the human body is about 75.0 mV and carries a current of about 0.200 mA. How much power does the neuron release?

> Batteries are rated in terms of ampere - hours (A · h). For example, a battery that can deliver a current of 3.0 A for 5.0 h is rated at 15 A · h. (a) What is the total energy, in kilowatt - hours, stored in a 12 - V battery rated at 55 A · h? (b) At $0.

> A copper cable is designed to carry a current of 300. A with a power loss of 2.00 W/m. What is the required radius of this cable?

> A certain toaster has a heating element made of Nichrome resistance wire. When the toaster is first connected to a 120. - V source of potential difference (and the wire is at a temperature of 20.0°C), the initial current is 1.80 A but the current begins

> Light-bulb A is marked “25.0 W 120. V,” and light-bulb B is marked “100. W 120. V.” These labels mean that each light-bulb has its respective power delivered to it when it is connected to a constant 120. - V source. (a) Find the resistance of each light-

> A typical cell phone consumes an average of about 1.00 W of electrical power and operates on 3.80 V. (a) What average current does the phone draw from its battery? (b) Calculate the energy stored in a fully charged battery if the phone requires charging

> A typical lightning bolt may last for 0.200 s and transfer 1.00 x 1020 electrons. Calculate the average current in the lightning bolt.

> The heating element of a coffeemaker operates at 120. V and carries a current of 2.00 A. Assuming the water absorbs all the energy converted by the resistor, calculate how long it takes to heat 0.500 kg of water from room temperature (23.0°C) to the boil

> A portable coffee heater supplies a potential difference of 12.0 V across a Nichrome heating element with a resistance of 2.00 Ω. (a) Calculate the power consumed by the heater. (b) How many minutes would it take to heat 1.00 kg of coffee from 20.0°C to

> Residential building codes typically require the use of 12 - gauge copper wire (diameter 0.205 cm) for wiring receptacles. Such circuits carry currents as large as 20.0 A. If a wire of smaller diameter (with a higher gauge number) carried that much curre

> A 1.50-kg iron horseshoe initially at 600°C is dropped into a bucket containing 20.0 kg of water at 25.0°C. What is the final temperature of the water–horseshoe system? Ignore the heat capacity of the container and assume a negligible amount of water boi

> If electrical energy costs $0.12 per kilowatt - hour, how much does it cost to (a) Burn a 100 - W light-bulb for 24 h? (b) Operate an electric oven for 5.0 h if it carries a current of 20.0 A at 220 V?

> A 5.00 - V power supply provides a maximum current of 10.0 A. (a) Calculate the maximum power delivered by the power supply. (b) How many 2.00 - W cell phone chargers could be powered by the power supply? Include fractional numbers in your answer.

> A platinum resistance thermometer has resistances of 200.0 Ω when placed in a 0°C ice bath and 253.8 Ω when immersed in a crucible containing melting potassium. What is the melting point of potassium? Hint: First determine the resistance of the platinum

> In one form of plethysmograph (a device for measuring volume), a rubber capillary tube with an inside diameter of 1.00 mm is filled with mercury at 20°C. The resistance of the mercury is measured with the aid of electrodes sealed into the ends of the tub

> An engineer needs a resistor with a zero overall temperature coefficient of resistance at 20.0°C. She designs a pair of circular cylinders, one of carbon and one of Nichrome as shown in Figure P17.32. The device must have an overall resistance

> (a) A 34.5 - m length of copper wire at 20.0°C has a radius of 0.25 mm. If a potential difference of 9.0 V is applied across the length of the wire, determine the current in the wire. (b) If the wire is heated to 30.0°C while the 9.0 - V potential differ

> A wire 3.00 m long and 0.450 mm2 in cross - sectional area has a resistance of 41.0 Ω at 20.0°C. If its resistance increases to 41.4 Ω at 29.0°C, what is the temperature coefficient of resistivity?

> In the Bohr model of the hydrogen atom, an electron in the lowest energy state moves at a speed equal to 2.19 x 106 m/s in a circular path having a radius of 5.29 x 10-11 m. What is the effective current associated with this orbiting electron?

> At 20.0°C, the carbon resistor in an electric circuit connected to a 5.0 - V battery has a resistance of 2.0 x 102 Ω. What is the current in the circuit when the temperature of the carbon rises to 80.0°C?

> At what temperature will aluminum have a resistivity that is three times the resistivity of copper at room temperature?

> An aluminum calorimeter with a mass of 0.100 kg contains 0.250 kg of water. The calorimeter and water are in thermal equilibrium at 10.0°C. Two metallic blocks are placed into the water. One is a 50.0-g piece of copper at 80.0°C. Th

> An air-filled parallel-plate capacitor with capacitance C0 stores charge Q on plates separated by distance d. The potential difference across the plates is ΔV0 and the energy stored is PEC,0. If the capacitor is disconnected from its voltage source and t

> Gold is the most ductile of all metals. For example, one gram of gold can be drawn into a wire 2.40 km long. The density of gold is 19.3 x 103 kg/m3, and its resistivity is 2.44 x 10-8 Ω · m. What is the resistance of such a wire at 20.0°C?

> A length of aluminum wire has a resistance of 30.0 Ω at 20.0°C. When the wire is warmed in an oven and reaches thermal equilibrium, the resistance of the wire increases to 46.2 Ω. (a) Neglecting thermal expansion, find the temperature of the oven. (b) Qu

> Digital thermometers often make use of thermistors, a type of resistor with resistance that varies with temperature more than standard resistors. Find the temperature coefficient of resistivity for a linear thermistor with resistances of 75.0 Ω at 0.00°C

> If a certain silver wire has a resistance of 6.00 Ω at 20.0°C, what resistance will it have at 34.0°C?

> Starting from Ohm’s law, show that E = Jρ, where E is the magnitude of the electric field (assumed constant) and J = I/A is called the current density. The result is in fact true in general.

> The human body can exhibit a wide range of resistances to current depending on the path of the current, contact area, and sweatiness of the skin. Suppose the resistance across the chest from the left hand to the right hand is 1.0 x 106 Ω. (a) How much vo

> The resistivity of copper is 1.70 x 10-8 Ω · m. (a) Find the resistance of a copper wire with a radius of 1.29 mm and a length of 1.00 m. (b) Calculate the volume of copper in the wire. (c) Suppose that volume of copper is formed into a new wire with a l

> A rectangular block of copper has sides of length 10. cm, 20. cm, and 40. cm. If the block is connected to a 6.0 - V source across two of its opposite faces, what are (a) The maximum current and (b) The minimum current the block can carry?

> A copper wire has a circular cross section with a radius of 1.25 mm. (a) If the wire carries a current of 3.70 A, find the drift speed of electrons in the wire. (Take the density of mobile charge carriers in copper to be n = 1.10 x 1029 electrons/m3.) (b

> A wire 50.0 m long and 2.00 mm in diameter is connected to a source with a potential difference of 9.11 V, and the current is found to be 36.0 A. Assume a temperature of 20°C and, using Table 17.1, identify the metal out of which the wire is m

> A large room in a house holds 975 kg of dry air at 30.0°C. A woman opens a window briefly and a cool breeze brings in an additional 50.0 kg of dry air at 18.0°C. At what temperature will the two air masses come into thermal equilibrium, assuming they for

> The current supplied by a battery in a portable device is typically 0.15 A. Find the number of electrons passing through the device in one hour.

> A potential difference of 12 V is found to produce a current of 0.40 A in a 3.2 - m length of wire with a uniform radius of 0.40 cm. What is (a) The resistance of the wire? (b) The resistivity of the wire?

> A wire of diameter 0.800 mm and length 25.0 m has a measured resistance of 1.60 Ω. What is the resistivity of the wire?

> Suppose you wish to fabricate a uniform wire out of 1.00 g of copper. If the wire is to have a resistance R = 0.500 Ω, and if all the copper is to be used, what will be (a) The length and (b) The diameter of the wire?

> A person notices a mild shock if the current along a path through the thumb and index finger exceeds 80. μA. Compare the maximum possible voltage without shock across the thumb and index finger with a dry - skin resistance of 4.0 x 105 Ω and a wet - skin

> Germanium is a semiconducting metal with a resistivity of 0.460 Ω · m. (a) Determine the current per unit area through a 5.00 - V germanium junction with a length of 2.00 mm. (b) Find the current through the junction if its cross - sectional area is 2.00

> A voltmeter connected across the terminals of a tungsten - filament light bulb measures 115 V when an ammeter in line with the bulb registers a current of 0.522 A. (a) Find the resistance of the light bulb. (b) Find the resistivity of tungsten at the bul

> An electric heater carries a current of 13.5 A when operating at a voltage of 1.20 x 102 V. What is the resistance of the heater?

> If a current of 80.0 mA exists in a metal wire, (a) How many electrons flow past a given cross section of the wire in 10.0 min? (b) In what direction do the electrons travel with respect to the current?

> A medium-sized banana provides about 105 Calories of energy. (a) Convert 105 Cal to joules. (b) Suppose that amount of energy is transformed into kinetic energy of a 1.00-kg object initially at rest. Calculate the final speed of the object. (c) If that s

> An ionized oxygen molecule (O2+) at point A has charge +e and moves at 2.00 x 103 m/s in the positive x - direction. A constant electric force in the negative x - direction slows the molecule to a stop at point B, a distance of 0.750 mm past A on the x -

> (a) Find the potential difference ΔVe required to stop an electron (called a “stopping potential”) moving with an initial speed of 2.85 x 107 m/s. (b) Would a proton traveling at the same speed require a greater or lesser magnitude potential difference?

> An electron is fired at a speed v0 = 5.6 x 106 m/s and at an angle θ0 = -45° between two parallel conducting plates that are D = 2.0 mm apart, as in Figure P16.72. If the voltage difference between the plates is ΔV = 1

> Metal sphere A of radius 12.0 cm carries 6.00 μC of charge, and metal sphere B of radius 18.0 cm carries -4.00 μC of charge. If the two spheres are attached by a very long conducting thread, what is the final distribution of charge on the two spheres?

> Two positive charges each of charge q are fixed on the y - axis, one at y = d and the other at y = -d as in Figure P16.70. A third positive charge 2q located on the x - axis at x = 2d is released from rest. Find symbolic expressions for (a) The total ele

> Oppositely charged parallel plates are separated by 5.33 mm. A potential difference of 600. V exists between the plates. (a) What is the magnitude of the electric field between the plates? (b) What is the magnitude of the force on an electron between the

> Capacitors C1 = 6.0 μF and C2 = 2.0 μF are charged as a parallel combination across a 250 - V battery. The capacitors are disconnected from the battery and from each other. They are then connected positive plate to negative plate and negative plate to po

> When a certain air - filled parallel - plate capacitor is connected across a battery, it acquires a charge of 150. μC on each plate. While the battery connection is maintained, a dielectric slab is inserted into, and fills, the region between the plates.

> The immediate cause of many deaths is ventricular fibrillation, an uncoordinated quivering of the heart, as opposed to proper beating. An electric shock to the chest can cause momentary paralysis of the heart muscle, after which the heart will sometimes

> A spherical capacitor consists of a spherical conducting shell of radius b and charge -Q concentric with a smaller conducting sphere of radius a and charge Q. (a) Find the capacitance of this device. (b) Show that as the radius b of the outer sphere appr

> An aluminum cup contains 225 g of water and a 40-g copper stirrer, all at 27°C. A 400-g sample of silver at an initial temperature of 87°C is placed in the water. The stirrer is used to stir the mixture until it reaches its final equilibrium temperature

> Find the equivalent capacitance of the group of capacitors shown in Figure P16.65. Figure P16.65:

> Two charges of 1.0 μC and -2.0 μC are 0.50 m apart at two vertices of an equilateral triangle as in Figure P16.64. (a) What is the electric potential due to the 1.0-μC charge at the third vertex, point P? (b) Wha

> A parallel-plate capacitor is constructed using a dielectric material whose dielectric constant is 3.00 and whose dielectric strength is 2.00 x 108 V/m. The desired capacitance is 0.250 μF, and the capacitor must withstand a maximum potential difference

> Two capacitors give an equivalent capacitance of Cp when connected in parallel and an equivalent capacitance of Cs when connected in series. What is the capacitance of each capacitor?

> A parallel-plate capacitor with a plate separation d has a capacitance C0 in the absence of a dielectric. A slab of dielectric material of dielectric constant k and thickness d/3 is then inserted between the plates as in Figure P16.61a. Show that the cap

> For the system of four capacitors shown in Figure P16.41, find (a) The total energy stored in the system and (b) The energy stored by each capacitor. (c) Compare the sum of the answers in part (b) with your result to part (a) and explain your observation

> Three parallel-plate capacitors are constructed, each having the same plate area A and with C1 having plate spacing d1, C2 having plate spacing d2, and C3 having plate spacing d3. Show that the total capacitance C of the three capacitors connected in ser

> When a potential difference of 150. V is applied to the plates of an air-filled parallel-plate capacitor, the plates carry a surface charge density of 3.00 x 10-10 C/cm2. What is the spacing between the plates?

> A model of a red blood cell portrays the cell as a spherical capacitor, a positively charged liquid sphere of surface area A separated from the surrounding negatively charged fluid by a membrane of thickness t. Tiny electrodes introduced into the interio

> Lead pellets, each of mass 1.00 g, are heated to 200.°C. How many pellets must be added to 0.500 kg of water that is initially at 20.0°C to make the equilibrium temperature 25.0°C? Neglect any energy transfer to or from the container.

> A parallel-plate capacitor has plates of area A = 7.00 x 10-2 m2 separated by distance d = 2.00 x 10-4 m. (a) Calculate the capacitance if the space between the plates is filled with air. What is the capacitance if the space is filled half with air and h

> Determine (a) The capacitance and (b) The maximum voltage that can be applied to a Teflon-filled parallel-plate capacitor having a plate area of 175 cm2 and an insulation thickness of 0.0400 mm.

> (a) How much charge can be placed on a capacitor with air between the plates before it breaks down if the area of each plate is 5.00 cm2? (b) Find the maximum charge if polystyrene is used between the plates instead of air. Assume the dielectric strength

> The voltage across an air-filled parallel-plate capacitor is measured to be 85.0 V. When a dielectric is inserted and completely fills the space between the plates as in Figure P16.53, the voltage drops to 25.0 V. (a) What is the dielectric constant of t

> Each plate of a 5.00 μF capacitor stores 60.0 μC of charge. (a) Find the potential difference across the plates. (b) How much energy is stored in the capacitor?

> A parallel-plate capacitor has capacitance 3.00 μF. (a) How much energy is stored in the capacitor if it is connected to a 6.00-V battery? (b) If the battery is disconnected and the distance between the charged plates doubled, what is the energy stored?

> Two capacitors, C1 = 18.0 μF and C2 = 36.0 μF, are connected in series, and a 12.0-V battery is connected across them. (a) Find the equivalent capacitance, and the energy contained in this equivalent capacitor. (b) Find the energy stored in each individu

> A constant electric field accelerates a proton from rest through a distance of 2.00 m to a speed of 1.50 x 105 m/s. (a) Find the change in the proton’s kinetic energy. (b) Find the change in the system’s electric potential energy. (c) Calculate the magni

> A 12.0-V battery is connected to a 4.50-μF capacitor. How much energy is stored in the capacitor?

> Four capacitors are connected as shown in Figure P16.48. (a) Find the equivalent capacitance between points a and b. (b) Calculate the charge on each capacitor, taking ΔVab = 15.0 V. Figure P16.48:

> What mass of water at 25.0°C must be allowed to come to thermal equilibrium with a 1.85-kg cube of aluminum initially at 1.50 x 102°C to lower the temperature of the aluminum to 65.0°C? Assume any water turned to steam subsequently recondenses.

> A 1.00-μF capacitor is charged by being connected across a 10.0-V battery. It is then disconnected from the battery and connected across an un-charged 2.00-μF capacitor. Determine the resulting charge on each capacitor.

> (a) Find the equivalent capacitance between points a and b for the group of capacitors connected as shown in Figure P16.46 if C1 = 5.00 μF, C2 = 10.00 μF, and C3 = 2.00 μF. (b) If the potential between points a a

> A 25.0-μF capacitor and a 40.0-μF capacitor are charged by being connected across separate 50.0-V batteries. (a) Determine the resulting charge on each capacitor. (b) The capacitors are then disconnected from their batteries and connected to each other,

> Three capacitors are connected to a battery as shown in Figure P16.44. Their capacitances are C1 = 3C, C2 = C, and C3 = 5C. (a) What is the equivalent capacitance of this set of capacitors? (b) State the ranking of the capacitors according to the charge

> Find the charge on each of the capacitors in Figure P16.43. Figure P16.43:

> Consider the combination of capacitors in Figure P16.42. (a) Find the equivalent single capacitance of the two capacitors in series and redraw the diagram (called diagram 1) with this equivalent capacitance. (b) In diagram 1, find the equivalent capacita

> For the system of capacitors shown in Figure P16.41, find (a) The equivalent capacitance of the system, (b) The charge on each capacitor, and (c) The potential difference across each capacitor. Figure P16.41:

> Two capacitors give an equivalent capacitance of 9.00 pF when connected in parallel and an equivalent capacitance of 2.00 pF when connected in series. What is the capacitance of each capacitor?

> Cathode ray tubes (CRTs) used in old-style televisions have been replaced by modern LCD and LED screens. Part of the CRT included a set of accelerating plates separated by a distance of about 1.50 cm. If the potential difference across the plates was 25.

> Find (a) The equivalent capacitance of the capacitors in Figure P16.39, (b) The charge on each capacitor, and (c) The potential difference across each capacitor. Figure P16.39:

> In the summer of 1958 in St. Petersburg, Florida, a new sidewalk was poured near the childhood home of one of the authors. No expansion joints were supplied, and by mid- July, the sidewalk had been completely destroyed by thermal expansion and had to be

> Two capacitors, C1 = 5.00 μF and C2 = 12.0 μF, are connected in parallel, and the resulting combination is connected to a 9.00-V battery. Find (a) The equivalent capacitance of the combination, (b) The potential difference across each capacitor, and (c)