EBK PHYSICS FOR SCIENTISTS AND ENGINEER
9th Edition
ISBN: 9780100454897
Author: Jewett
Publisher: YUZU
expand_more
expand_more
format_list_bulleted
Videos
Textbook Question
Chapter 28, Problem 28.48P
Turn on your desk lamp. Pick up the cord, with your thumb and index finger spanning the width of the cord. (a) Compute an order-of-magnitude estimate for the current in your hand. Assume the conductor inside the lamp cord next to your thumb is at potential ~ 102 V at a typical instant and the conductor next to your index finger is at ground potential (0 V). The resistance of your hand depends strongly on the thickness and the moisture content of the outer layers of your skin. Assume the resistance of your hand between fingertip and thumb tip is ~ 104 Ω. You may model the cord as having rubber insulation. State the other quantities you measure or estimate and their values. Explain your reasoning. (b) Suppose your body is isolated from any other charges or currents. In order-of-magnitude terms, estimate the potential difference between your thumb where it contacts the cord and your finger where it touches the cord.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
A straight, cylindrical wire lying along the x axis has a length L and a diameter d. It is made of a material described by Ohm’s law with a resistivity ρ. Assume potential V is maintained at the left end of the wire at x = 0. Also assume the potential is zero at x = L. In terms of L, d, V, ρ, and physical constants, derive expressions for (a) the magnitude and direction of the electric field in the wire, (b) the resistance of the wire, (c) the magnitude and direction of the electric current in the wire, and (d) the current density in the wire. (e) Show that E = ρJ.
Three wires, of the same diameter, are connected in turn between two points maintained at a constant potential difference. Their resistivities and lengths are r and L (wire A), 1.2r and 1.2L (wire B), and 0.9r and L (wire C). Rank the wires according to the rate at which energy is transferred to thermal energy within them, greatest first.
Whale and Kanmuro are two islands located in the Chimera archipelago. These two are separated by a distance of 20 miles. A power link is to
be established between them. The power link delivers a maximum power of 600 MW at full capacity with an operating voltage of 500 kV.
Solve for the resistivity of the cable, assuming a conductor diameter of 1.5 cm. Express your answer in uQ-m.
Chapter 28 Solutions
EBK PHYSICS FOR SCIENTISTS AND ENGINEER
Ch. 28 - To maximize the percentage of the power from the...Ch. 28 - With the switch in the circuit of Figure 27.4a...Ch. 28 - With the switch in the circuit of Figure 27.6a...Ch. 28 - Prob. 28.4QQCh. 28 - Consider the circuit in Figure 27.17 and assume...Ch. 28 - Is a circuit breaker wired (a) in series with the...Ch. 28 - A battery has some internal resistance. (i) Clan...Ch. 28 - The terminals of a battery are connected across...Ch. 28 - When operating on a 120-V circuit, an electric...Ch. 28 - If the terminals of a battery with zero internal...
Ch. 28 - Prob. 28.6OQCh. 28 - What is the time constant of the circuit shown in...Ch. 28 - When resistors with different resistances are...Ch. 28 - When resistors with different resistances are...Ch. 28 - The terminals of a battery are connected across...Ch. 28 - Are the two headlights of a car wired (a) in...Ch. 28 - In the circuit shown in Figure OQ28.12, each...Ch. 28 - Prob. 28.13OQCh. 28 - A circuit consists of three identical lamps...Ch. 28 - A series circuit consists of three identical lamps...Ch. 28 - Suppose a parachutist lands on a high-voltage wire...Ch. 28 - A student claims that the second of two lightbulbs...Ch. 28 - Why is ii possible for a bird to sit on a...Ch. 28 - Given three lightbulbs and a battery, sketch as...Ch. 28 - Prob. 28.5CQCh. 28 - Referring to Figure CQ28.6, describe what happens...Ch. 28 - Prob. 28.7CQCh. 28 - (a) What advantage does 120-V operation offer over...Ch. 28 - Prob. 28.9CQCh. 28 - Prob. 28.10CQCh. 28 - A battery has an emf of 15.0 V. The terminal...Ch. 28 - Two 1.50-V batterieswith their positive terminals...Ch. 28 - An automobile battery has an emf of 12.6 V and 171...Ch. 28 - As in Example 27.2, consider a power supply with...Ch. 28 - Three 100- resistors are connected as shown in...Ch. 28 - Prob. 28.6PCh. 28 - What is the equivalent resistance of the...Ch. 28 - Consider the two circuits shown in Figure P27.5 in...Ch. 28 - Consider the circuit shown in Figure P28.9. Find...Ch. 28 - (a) You need a 45- resistor, but the stockroom has...Ch. 28 - A battery with = 6.00 V and no internal...Ch. 28 - A battery with emf and no internal resistance...Ch. 28 - (a) Kind the equivalent resistance between points...Ch. 28 - (a) When the switch S in the circuit of Figure...Ch. 28 - Prob. 28.15PCh. 28 - Four resistors are connected to a battery as shown...Ch. 28 - Consider die combination of resistors shown in...Ch. 28 - For the purpose of measuring the electric...Ch. 28 - Calculate the power delivered to each resistor in...Ch. 28 - Why is the following situation impossible? A...Ch. 28 - Consider the circuit shown in Figure P28.21 on...Ch. 28 - In Figure P28.22, show how to add just enough...Ch. 28 - The circuit shown in Figure P27.17 is connected...Ch. 28 - For the circuit shown in Figure P28.24, calculate...Ch. 28 - What are the expected readings of (a) the ideal...Ch. 28 - The following equations describe an electric...Ch. 28 - Taking R = 1.00 k and = 250 V in Figure P27.19,...Ch. 28 - You have a faculty position at a community college...Ch. 28 - The ammeter shown in Figure P28.29 reads 2.00 A....Ch. 28 - In the circuit of Figure P28.30, determine (a) the...Ch. 28 - Using Kirchhoffs rules, (a) find (he current in...Ch. 28 - In the circuit of Figure P27.20, the current I1 =...Ch. 28 - In Figure P28.33, find (a) the current in each...Ch. 28 - For the circuit shown in Figure P27.22, we wish to...Ch. 28 - Find the potential difference across each resistor...Ch. 28 - (a) Can the circuit shown in Figure P27.21 be...Ch. 28 - An uncharged capacitor and a resistor are...Ch. 28 - Consider a series RC circuit as in Figure P28.38...Ch. 28 - A 2.00-nF capacitor with an initial charge of 5.10...Ch. 28 - A 10.0-F capacitor is charged by a 10.0-V battery...Ch. 28 - In the circuit of Figure P27.25, the switch S has...Ch. 28 - In the circuit of Figure P27.25, the switch S has...Ch. 28 - The circuit in Figure P28.43 has been connected...Ch. 28 - Show that the integral 0e2t/RCdtin Example 27.11...Ch. 28 - A charged capacitor is connected to a resistor and...Ch. 28 - Prob. 28.46PCh. 28 - Prob. 28.47PCh. 28 - Turn on your desk lamp. Pick up the cord, with...Ch. 28 - Assume you have a battery of emf and three...Ch. 28 - Find the equivalent resistance between points a...Ch. 28 - Four 1.50-V AA batteries in series are used to...Ch. 28 - Four resistors are connected in parallel across a...Ch. 28 - The circuit in Figure P27.35 has been connected...Ch. 28 - The circuit in Figure P27.34a consists of three...Ch. 28 - For the circuit shown in Figure P28.55. the ideal...Ch. 28 - The resistance between terminals a and b in Figure...Ch. 28 - (a) Calculate the potential difference between...Ch. 28 - Why is the following situation impossible? A...Ch. 28 - A rechargeable battery has an emf of 13.2 V and an...Ch. 28 - Find (a) the equivalent resistance of the circuit...Ch. 28 - When two unknown resistors are connected in series...Ch. 28 - When two unknown resistors are connected in series...Ch. 28 - The- pair of capacitors in Figure P28.63 are fully...Ch. 28 - A power supply has an open-circuit voltage of 40.0...Ch. 28 - The circuit in Figure P27.41 contains two...Ch. 28 - Two resistors R1 and R2 are in parallel with each...Ch. 28 - Prob. 28.67APCh. 28 - A battery is used to charge a capacitor through a...Ch. 28 - A young man owns a canister vacuum cleaner marked...Ch. 28 - (a) Determine the equilibrium charge on the...Ch. 28 - Switch S shown in Figure P28.71 has been closed...Ch. 28 - Three identical 60.0-W, 120-V lightbulbs are...Ch. 28 - A regular tetrahedron is a pyramid with a...Ch. 28 - An ideal voltmeter connected across a certain...Ch. 28 - In Figure P27.47, suppose the switch has been...Ch. 28 - Figure P27.48 shows a circuit model for the...Ch. 28 - The student engineer of a campus radio station...Ch. 28 - The circuit shown in Figure P28.78 is set up in...Ch. 28 - An electric teakettle has a multiposition switch...Ch. 28 - A voltage V is applied to a series configuration...Ch. 28 - In places such as hospital operating rooms or...Ch. 28 - The switch in Figure P27.51a closes when Vc23Vand...Ch. 28 - The resistor R in Figure P28.83 receives 20.0 W of...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- A 0.900-V potential difference is maintained across a 1.50-m length of tungsten wire that has a cross-sectional area of 0.600 mm2. What is the current in the wire?arrow_forwardThe student engineer of a campus radio station wishes to verify the effectiveness of the lightning rod on the antenna mast (Fig. P21.71). The unknown resistance Rx is between points C and E. Point E is a true ground, but it is inaccessible for direct measurement because this stratum is several meters below the Earths surface. Two identical rods are driven into the ground at A and B, introducing an unknown resistance Ry. The procedure is as follows. Measure resistance R1 between points A and B, then connect A and B with a heavy conducting wire and measure resistance R2 between points A and C. (a) Derive an equation for Rx in terms of the observable resistances, R1 and R2. (b) A satisfactory ground resistance would be Rx 2.00 . Is the grounding of the station adequate if measurements give R1 = 13.0 and R2 = 6.00 ? Explain. Figure P21.71arrow_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
- Measurements made during severe electrical storms reveal that lightning bolts can carry as much as 30 C of charge and can travel between a cloud and the ground in time intervals of around 100 μμs (and sometimes even shorter). Potential differences have been measured as high as 400 million volts. 1)What is the current in such a lightning strike? (Express your answer to two significant figures.) 2)What is the resistance of the air during such a strike? (Express your answer to two significant figures.) 3)How much energy is transferred during a severe strike? (Express your answer to two significant figures.) 4)What mass of water at 100∘C could the lightning bolt in part (3) evaporate? The latent heat of vaporization of water at 100∘C is LV=2260 kJ/kg. (Express your answer to two significant figures.)arrow_forwardYou are working with an oceanographer who is studying how the ion concentration in seawater depends on depth. She shows you the device that she uses to measure the resistivity of water from a boat. It consists of a pair of concentric metallic cylinders at the end of a cable (as shown). Seawater flows freely between the two cylindrical shells. She makes a measurement by lowering the device into the water and applying a potential difference ΔV between the inner and outer cylinders. This produces an outward radial current I in the seawater between the shells. She shows you the current and voltage data for the water at a particular depth and is then called away to answer a long call on her cellphone about a laboratory issue back on the mainland. As she leaves, she says, “Have the resistivity of the water calculated when I get back.” She forgot to show you any tables or formulas to use to determine the resistivity, so you are on your own. Quick! Find an expression for the resistivity in…arrow_forwardConsider a portion of a cell membrane that has a thickness of 7.50 nm and 1.8 pm x 1.8 um in area. A measurement of the potential difference across the inner and outer surfaces of the membrane gives a reading of 91.5 mV. The resistivity of the membrane material is 1.30 x 107n - m. (a) Determine the amount of current that flows through this portion of the membrane. (b) By what factor does the current change if the side dimensions of the membrane portion is halved? The other values do not change. O increase by a factor of 4 O decrease by a factor of 4 O increase by a factor of 2 o decrease by a factor of 8 O decrease by a factor of 2arrow_forward
- A wire with resistance R is connected to the terminals of a 6.0 V battery. What is the potential difference ΔVends between the ends of the wire and the current I through it if the wire has the following resistances? (a) 1.0 Ω (b) 2.0 Ω (c) 3.0 Ω.arrow_forwardA copper wire of radius a = 0.330 mm has an aluminum jacket of outer radius b = 0.476 mm. There is a current i = 1.50 A in the composite wire. Take the resistivity for copper and aluminum to be 1.69 x 1080-m and 2.75 x 1080-m. Calculate the current in (a) the copper and (b) the aluminum. (c) If a potential difference V = 18.0 V between the ends maintains the current, what is the length in meters of the composite wire? (a) Number i (b) Number (c) Number i Units Units Unitsarrow_forwardA certain resistor has a uniform cross-sectional area of 5.0 mm 2 and a resistivity of 2x10 -6 Ω-m. A 15-V electric potential is applied across the ends of the resistor causing a 4.0x10 -3 A current. Find (a) the resistance of the resistor and (b) the resistor’s length.arrow_forward
- A rod of semiconducting material of Length L=2 m and cross-sectional area A=4 mm2 lies along the x-axis between x=0 and x=L. The material obeys ohm’s Law, and its resistivity varies along the rod according to ρ = ρ0*( 1 - x2/L2) where ρ0=3 x 10-4 Ω.m. The end of the rod at x=0 is at potential V0=25 V greater than the end at x=L. What is the electric potential, in units of volt, in the rod at x=L/2?arrow_forwardA cylindrical resistor of radius 5.0 mm and length 2.0 cm is made of material that has a resistivity of 3.5 * 10-5 ohm m.What are (a) the magnitude of the current density and (b) the potential difference when the energy dissipation rate in the resistor is 1.0W?arrow_forwardA straight, cylindrical wire lying along the x axis has a length of 0.500 m and a diameter of 0.200 mm. It is made of a material described by Ohm’s law with a resistivity of ρ = 4.00 x 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 = 0.500 m. Find (a) the magnitude and direction of the electric field in the wire, (b) the resistance of the wire, (c) the magnitude and direction of the electric current in the wire, and (d) the current density in the wire. (e) Show that E = ρJ.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Physics for Scientists and Engineers: Foundations...
Physics
ISBN:9781133939146
Author:Katz, Debora M.
Publisher:Cengage Learning
How To Solve Any Resistors In Series and Parallel Combination Circuit Problems in Physics; Author: The Organic Chemistry Tutor;https://www.youtube.com/watch?v=eFlJy0cPbsY;License: Standard YouTube License, CC-BY