1 Introduction, Measurement, Estimating 2 Describing Motion: Kinematics In One Dimension 3 Kinematics In Two Or Three Dimensions; Vectors 4 Dynamics: Newton's Laws Of Motion 5 Using Newton's Laws: Friction, Circular Motion, Drag Forces 6 Gravitation And Newton's Synthesis 7 Work And Energy 8 Conservation Of Energy 9 Linear Momentum 10 Rotationalmotion 11 Angular Momentum; General Rotation 12 Static Equilibrium; Elasticity And Fracture 13 Fluids 14 Oscillations 15 Wave Motion 16 Sound 17 Temperature, Thermal Expansion And The Ideal Gas Law 18 Kinetic Theory Of Gases 19 Heat And The First Law Of Thermodynamics 20 Second Law Of Thermodynamics 21 Electric Charge And Electric Field 22 Gauss's Law 23 Electric Potential 24 Capacitance, Dielectrics, Electric Energy Storage 25 Electric Currents And Resistance 26 Dc Circuits 27 Magnetism 28 Sources Of Magnetic Field 29 Electromagnetic Induction And Faraday's Law 30 Inductance, Electromagnetic Oscillations, And Ac Circuits 31 Maxwell's Equation And Electromagnetic Waves 32 Light: Reflection And Refraction 33 Lenses And Optical Instruments 34 The Wave Nature Of Light: Interference 35 Diffraction And Polarization 36 Special Theory Of Relativity 37 Early Quantum Theory And Models Of The Atom 38 Quantum Mechanics 39 Quantum Mechanics Of Atoms 40 Molecules And Solids 41 Nuclear Physics And Radioactivity 42 Nuclear Energy; Effects And Uses Of Radiation 43 Elementary Particles 44 Astrophysics And Cosmology expand_more
25.1 The Electric Battery 25.2 Electric Current 25.3 Ohm’s Law: Resistance And Resistors 25.4 Resistivity 25.5 Electric Power 25.6 Power In Household Circuits 25.7 Alternating Current 25.8 Microscopic View Of Electric Current: Current Density And Drift Velocity 25.9 Superconductivity 25.10 Electrical Conduction In The Nervous System Chapter Questions expand_more
Problem 1Q: What quantity is measured by a battery rating given in ampere-hours (Ah)? Problem 2Q: When an electric cell is connected to a circuit, electrons flow away from the negative terminal in... Problem 3Q: When a flashlight is operated, what is being used up: battery current, battery voltage, battery... Problem 4Q: One terminal of a car battery is said to be connected to ground. Since it is not really connected to... Problem 5Q: When you turn on a water faucet, the water usually flows immediately. You dont have to wait for... Problem 6Q: Can a copper wire and an aluminum wire of the same length have the same resistance? Explain. Problem 7Q: The equation P = V2/R indicates that the power dissipated in a resistor decreases if the resistance... Problem 8Q: What happens when a lightbulb burns out? Problem 9Q: If the resistance of a small immersion heater (to heat water for tea or soup. Fig. 2533) was... Problem 10Q Problem 11Q: Explain why lightbulbs almost always burn out just as they are turned on and not after they have... Problem 12Q: Which draws more current, a 100-W lightbulb or a 75-W bulb? Which has the higher resistance? Problem 13Q: Electric power is transferred over large distances at very high voltages. Explain how the high... Problem 14Q: A 15-A fuse blows repeatedly. Why is it dangerous to replace this fuse with a 25-A fuse? Problem 15Q: When electric lights are operated on low-frequency ac (say, 5 Hz), they flicker noticeably. Why? Problem 16Q: Driven by ac power, the same electrons pass back and forth through your reading lamp over and over... Problem 17Q: The heating element in a toaster is made of Nichrome wire. Immediately after the toaster is turned... Problem 18Q: Is current used up in a resistor? Explain. Problem 19Q: Compare the drift velocities and electric currents in two wires that are geometrically identical and... Problem 20Q: A voltage V is connected across a wire of length l and radius r. How is the electron drift velocity... Problem 21Q: Why is it more dangerous to turn on an electric appliance when you are standing outside in bare feet... Problem 1P: ( A current of 1.30 A flows in a wire. How many electrons are flowing past any point in the wire per... Problem 2P: (I) A service station charges a battery using a current of 6.7-A for 5.0 h. How much charge passes... Problem 3P: (I) What is the current in amperes if 1200 Na+ ions flow across a cell membrane in 3.5 s? The charge... Problem 4P: (I) What is the resistance of a toaster if 120V produces a current of 4.2 A? Problem 5P: (II) An electric clothes dryer has a heating element with a resistance of 8.6 . (a) What is the... Problem 6P: (II) A hair dryer draws 9.5 A when plugged into a 120-V line. (a) What is its resistance? (b) How... Problem 7P: (II) A 4.5-V battery is connected to a bulb whose resistance is 1.6 How many electrons leave the... Problem 8P: (II) A bird stands on a dc electric transmission line carrying 3100 A (Fig. 2534). The line has 2.5 ... Problem 9P: (II) A 12-V battery causes a current of 0.60 A through a resistor. (a) What is its resistance, and... Problem 10P: (II) An electric device draws 6.50 A at 240 V. (a) If the voltage drops by 15%, what will be the... Problem 11P: (I) What is the diameter of a 1.00-m length of tungsten wire whose resistance is 0.32 ? Problem 12P: (I) What is the resistance of a 4.5-m length of copper wire 1.5 mm in diameter? Problem 13P: (II) Calculate the ratio of the resistance of 10.0 m of aluminum wire 2.0 mm in diameter, to 20.0 m... Problem 14P: (II) Can a 2.2-mm-diameter copper wire have the same resistance as a tungsten wire of the same... Problem 15P: (II) A sequence of potential differences V is applied across a wire (diameter = 0.32 mm, length = 11... Problem 16P: (II) How much would you have 10 raise the temperature of a copper wire (originally at 20C) to... Problem 17P: (II) A certain copper wire has a resistance of 10.0 . At what point along its length must the wire... Problem 18P: (II) Determine at what temperature aluminum will have the same resistivity as tungsten does at 20C. Problem 19P: (II) A 100-W lightbulb has a resistance of about 12 when cold (20C) and 140 when on (hot).... Problem 20P: (II) Compute the voltage drop along a 26-m length of household no. 14 copper wire (used in 15-A... Problem 21P: (II) Two aluminum wires have the same resistance. If one has twice the length of the other, what is... Problem 22P: (II) A rectangular solid made of carbon has sides of lengths 1.0 cm, 2.0 cm, and 4.0cm, lying along... Problem 23P: (II) A length of aluminum wire is connected to a precision 10.00-V power supply, and a current of... Problem 24P: (II) Small changes in the length of an object can be measured using a strain gauge sensor, which is... Problem 25P: (II) A length of wire is cut in half and the two lengths are wrapped together side by side to make a... Problem 26P: (III) For some applications, it is important that the value of a resistance not change with... Problem 27P: (III) Determine a formula for the total resistance of a spherical shell made of material whose... Problem 28P: (III) The filament of a lightbulb has a resistance of 12 at 20C and 140 when hot (as in Problem... Problem 29P: (III) A 10.0-m length of wire consists of 5.0 m of copper followed by 5.0 m of aluminum, both of... Problem 30P: (III) A hollow cylindrical resistor with inner radius r1 and outer radius r2, and length , is made... Problem 31P: (I) What is the maximum power consumption of a 3.0-V portable CD player that draws a maximum of... Problem 32P: (I) The heating element of an electric oven is designed to produce 3.3 kW of heat when connected to... Problem 33P: (I) What is the maximum voltage that can be applied across a 3.3-k resistor rated at 14 watt? Problem 34P: (I) (a) Determine the resistance of, and current through, a 75-W lightbulb connected to its proper... Problem 35P: (II) An electric power plant can produce electricity at a fixed power P, but the plant operator is... Problem 36P: (II) A 120-V hair dryer has two settings: 850 W and 1250 W. (a) At which setting do you expect the... Problem 37P: (II) A 115-V fish-tank heater is rated at 95W. Calculate (a) the current through the heater when it... Problem 38P: (II) You buy a 75-W lightbulb in Europe, where electricity is delivered to homes at 240 V. If you... Problem 39P: (II) How many kWh of energy does a 550-W toaster use in the morning if it is in operation for a... Problem 40P: (II) At 0.095/kWh, what does it cost to leave a 25-W porch light on day and night for a year? Problem 41P: (II) What is the total amount of energy stored in a 12-V, 75-A h car battery when it is fully... Problem 42P: (II) An ordinary flashlight uses two D-cell 1.5-V batteries connected in series as in Fig. 25-4b... Problem 43P: (II) How many 75-W lightbulbs, connected to 120V as in Fig. 2520, can be used without blowing a 15-A... Problem 44P: (II) An extension cord made of two wires of diameter 0.129cm (no. 16 copper wire) and of length 2 7m... Problem 45P: (II) A power station delivers 750kW of power at l2,000 V to a factory through wires with total... Problem 46P: (III) A small immersion heater can be used in a car to heat a cup of water for coffee or tea. If the... Problem 47P: (III) The current in an electromagnet connected to a 240-V line is 17.5 A. At what rate must cooling... Problem 48P: (III) A 1.0-m-long round tungsten wire is to reach a temperature of 3100K when a current of 15.0 A... Problem 49P: (I) Calculate the peak current in a 2.7-k resistor connected to a 220-V rms ac source. Problem 50P: (I) An ac voltage, whose peak value is 180 V, is across a 380- resistor. What are the rms and peak... Problem 51P: (II) Estimate the resistance of the 120-Vrms circuits in your house as seen by the power company,... Problem 52P: (II) The peak value of an alternating current in a 1500-W device is 5.4 A. What is the rms voltage... Problem 53P: (II) An 1800-W are welder is connected to a 660-Vrms ac line. Calculate (a) the peak voltage and (b)... Problem 54P: (II) (a) What is the maximum instantaneous power dissipated by a 2.5-hp pump connected to a 240-Vrms... Problem 55P: (II) A heater coil connected to a 240-Vrrms ac line has a resistance of 44 , (a) What is the average... Problem 56P: (II) For a time-dependent voltage V(t), which is periodic with period T, the rms voltage is defined... Problem 57P Problem 58P: (II) A 5.80-m length of 2.0-mm-diameter wire carries a 750-mA current when 22.0 mV is applied to its... Problem 59P: (II) At a point high in the Earths atmosphere. He2+ ions in a concentration of 2.8 1012/m3 are... Problem 60P: (I) What is the magnitude of the electric field across an axon membrane 1.0 10-8 m thick if the... Problem 61P: (II) A neuron is stimulated with an electric pulse. The action potential is detected at a point... Problem 62P: (III) During an action potential, Na+ ions move into the cell at a rate of about 3 107 mol/m2 s.... Problem 63GP: A person accidentally leaves a car with the lights on. If each of the two headlights uses 40 W and... Problem 64GP: How many coulombs are there in 1.00 ampere-hour? Problem 65GP: You want to design a portable electric blanket that runs on a 1.5-V battery. If you use copper wire... Problem 66GP: What is the average current drawn by a 1.0-hp 120-V motor? (1 hp = 746 W.) Problem 67GP Problem 68GP: The heating element of a 110-V, 1500-W heater is 3.5 m long. If it is made of iron, what must its... Problem 69GP: (a) A particular household uses a 1.8-kW healer 2.0 h/day (on time), four 100-W lightbulbs 6.0... Problem 70GP: A small city requires about 15 MW of power. Suppose that instead of using high-voltage lines to... Problem 71GP: A 1400-W hair dryer is designed for 117 V. (a) What will be the percentage change in power output if... Problem 72GP: The wiring in a house must be thick enough so it does not become so hot as to start a fire. What... Problem 73GP Problem 74GP: Suppose a current is given by the equation I = 1.80 sin 210t, where I is in amperes and t in... Problem 75GP: A microwave oven running at 65% efficiency delivers 950 W of energy per second to the interior. Find... Problem 76GP Problem 77GP: 220 V is applied to two different conductors made of the same material. One conductor is twice as... Problem 78GP: An electric heater is used to heat a room of volume 54 m3. Air is brought into the room at 5C and is... Problem 79GP: A 2800-W oven is connected to a 240-V source, (a) What is the resistance of the oven? (b) How long... Problem 80GP: A proposed electric vehicle makes use of storage batteries as us source of energy. Its mass is 1560... Problem 81GP: A 12.5- resistor is made from a coil of copper wire whose total mass is 15.5 g. What is the diameter... Problem 82GP: A fish-tank heater is rated at 95 W when connected to 120 V. The healing element is a coil of... Problem 83GP: A 100-W, 120-V lightbulb has a resistance of 12 when cold (20C) and 140 when on (hot). Calculate... Problem 84GP: In an automobile, the system voltage varies from about 12 V when the car is off to about 13.8 V when... Problem 85GP: The Tevatron accelerator at Fermilab (Illinois) is designed to carry an 11 -mA beam of protons... Problem 86GP: Lightbulb A is rated at 120 V and 40 W for household applications. Lightbulb B is rated at 12 V and... Problem 87GP: An air conditioner draws 14 A at 220-V ac. The connecting cord is copper wire with a diameter of... Problem 88GP: Copper wire of diameter 0.259 cm is used to connect a set of appliances at 120V, which draw 1750 W... Problem 89GP: Battery-powered electricity is very expensive compared with that available from a wall receptacle.... Problem 90GP: How far does an average electron move along the wires of a 550-W toaster during an alternating... Problem 91GP: A copper pipe has an inside diameter of 3.00 cm and an outside diameter of 5.00 cm (Fig. 2538). What... Problem 92GP: For the wire in Fig. 2539, whose diameter varies uniformly from a to b as shown, suppose a current I... Problem 93GP: The cross section of a portion of wire increases uniformly as shown in Fig. 2539 so it has the shape... Problem 94GP Problem 95GP: The level of liquid helium (temperature 4 K) in its storage lank can be monitored using a... Problem 96GP: (II) The resistance, R, of a particular thermistor as a function of temperature T is shown in this... format_list_bulleted