Question: For the circuit shown in Figure P18.

> At the equator, near the surface of Earth, the magnetic field is approximately 50.0 μT northward, and the electric field is about 100. N/C downward in fair weather. Find the gravitational, electric, and magnetic forces on an electron with an instantaneou

> Is the magnetic field created by a current loop uniform? Explain.

> A proton moving at 4.00 x 106 m/s through a magnetic field of magnitude 1.70 T experiences a magnetic force of magnitude 8.20 x 10-13 N. What is the angle between the proton’s velocity and the field?

> A magnet attracts a piece of iron. The iron can then attract another piece of iron. On the basis of domain alignment, explain what happens in each piece of iron.

> Electrons and protons travel from the Sun to the Earth at a typical velocity of 4.00 x 105 m/s in the positive x - direction. Thousands of miles from Earth, they interact with Earth’s magnetic field of magnitude 3.00 x 10-8 T in the positive z - directio

> Will a nail be attracted to either pole of a magnet? Explain what is happening inside the nail when it is placed near the magnet.

> A laboratory electromagnet produces a magnetic field of magnitude 1.50 T. A proton moves through this field with a speed of 6.00 x 106 m/s. (a) Find the magnitude of the maximum magnetic force that could be exerted on the proton. (b) What is the magnitud

> Can a constant magnetic field set a proton at rest into motion? Explain your answer.

> As a charged particle moves freely in a circular path in the presence of a constant magnetic field applied perpendicular to the particle’s velocity, the particle’s kinetic energy (a) Remains constant, (b) Increases, or (c) Decreases.

> The circuit in Figure P18.62 contains two resistors, R1 = 2.0 kΩ and R2 = 3.0 kΩ, and two capacitors, C1 = 2.0 μF and C2 = 3.0 μF, connected to a battery with emf ε = 120 V. If there are no

> A battery with an internal resistance of 10.0 Ω produces an open circuit voltage of 12.0 V. A variable load resistance with a range from 0 to 30.0 Ω is connected across the battery. (Note: A battery has a resistance that depends o

> For the network in Figure P18.60, show that the resistance between points a and b is Rab = 27/17 Ω. (Hint: Connect a battery with emf ε across points a and b and determine ε/I, where I is the current in the battery.)

> A voltage DV is applied to a series configuration of n resistors, each of resistance R. The circuit components are reconnected in a parallel configuration, and voltage ΔV is again applied. Show that the power consumed by the series configuration is 1/n2

> A circuit consists of three identical lamps, each of resistance R, connected to a battery as in Figure P18.53. (a) Calculate an expression for the equivalent resistance of the circuit when the switch is open. Repeat the calculation when the switch is clo

> The circuit in Figure P18.52a consists of three resistors and one battery with no internal resistance. (a) Find the current in the 5.00 - Ω resistor. (b) Find the power delivered to the 5.00 - Ω resistor. (c) In each of the circui

> When two unknown resistors are connected in series with a battery, the battery delivers 225 W and carries a total current of 5.00 A. For the same total current, 50.0 W is delivered when the resistors are connected in parallel. Determine the value of each

> Three 60.0 - W, 120 - V light-bulbs are connected across a 120 - V power source, as shown in Figure P18.50. Find (a) The total power delivered to the three bulbs and (b) The potential difference across each. Assume the resistance of each bulb is constant

> Figure P18.49 shows separate series and parallel circuits. (a) What is the ratio ΔVseries /ΔVparallel? (b) What is the ratio of the power dissipated by the resistors in the series to the parallel circuit, Pseries/Pparallel? Figur

> The resistor R in Figure P18.58 dissipates 20 W of power. Determine the value of R. Figure P18.58:

> For the circuit shown in Figure P18.48, the voltmeter reads 6.0 V and the ammeter reads 3.0 mA. Find (a) The value of R, (b) The emf of the battery, and (c) The voltage across the 3.0 – kΩ resistor. (d) What assumptions did

> (a) Calculate the potential difference between points a and b in Figure P18.47 and (b) Identify which point is at the higher potential. Figure P18.47:

> How many different resistance values can be constructed from a 2.0 - Ω, a 4.0 - Ω, and a 6.0 - Ω resistor? Show how you would get each resistance value either individually or by combining them.

> Using Figure 18.29b and the results of Problems 18.43d and 18.44a, find the power supplied by the axon per action potential. Figure 18.29b:

> Consider the model of the axon as a capacitor from Problem 43 and Figure P18.43. (a) How much energy does it take to restore the inner wall of the axon to -7.0 x 10-2 V, starting from +3.0 x 10-2 V? (b) Find the average current in the axon wall during th

> Assume a length of axon membrane of about 0.10 m is excited by an action potential (length excited = nerve speed x pulse duration = 50.0 m/s x 2.0 x 10-3 s = 0.10 m). In the resting state, the outer surface of the axon wall is charged positively with K+

> A coffee maker is rated at 1200 W, a toaster at 1100 W, and a waffle maker at 1400 W. The three appliances are connected in parallel to a common 120 - V household circuit. (a) What is the current in each appliance when operating independently? (b) What t

> A heating element in a stove is designed to dissipate 3.00 x 103 W when connected to 240. V. (a) Assuming the resistance is constant, calculate the current in the heating element if it is connected to 120. V. (b) Calculate the power it dissipates at that

> A 1 150 - W toaster and an 825 - W microwave oven are connected in parallel to the same 20.0 - A, 120 - V circuit. (a) Find the toaster’s resistance R. (b) If the microwave fails and is replaced, what maximum power rating can be used without tripping the

> What minimum number of 75 - W light-bulbs must be connected in parallel to a single 120 - V household circuit to trip a 30.0 - A circuit breaker?

> The student engineer of a campus radio station wishes to verify the effectiveness of the lightning rod on the antenna mast (Fig. P18.57). The unknown resistance Rx is between points C and E. Point E is a “true ground”

> The capacitor in Figure P18.35 is uncharged for t (a) t = 0, when the switch is closed, and (b) t = (, one time constant after the switch is closed. Figure P18.35:

> Figure P18.37 shows a simplified model of a cardiac defibrillator, a device used to resuscitate patients in ventricular fibrillation. When the switch S is toggled to the left, the capacitor C charges through the resistor R. When the switch is toggled to

> The RC charging circuit in a camera flash unit has a voltage source of 275 V and a capacitance of 125 μF. (a) Find its resistance R if the capacitor charges to 90.0% of its final value in 15.0 s. (b) Find the average current delivered to the flash bulb i

> Consider a series RC circuit as in Figure P18.35 for which R = 1.00 MΩ, C = 5.00 μF, and ε = 30.0 V. Find (a) The time constant of the circuit and (b) The maximum charge on the capacitor after the switch is thrown c

> An uncharged capacitor and a resistor are connected in series to a source of emf. If ε = 9.00 V, C = 20.0 μF, and R = 1.00 x 102 Ω, find (a) The time constant of the circuit, (b) The maximum charge on the capacitor, and (c) The charge on the capacitor af

> Consider the series RC circuit shown in Figure 18.17 for which R = 75.0 kΩ, C = 25.0 μF, and ε = 12.0 V. Find (a) The time constant of the circuit and (b) The charge on the capacitor one time constant after the swit

> Show that ( = RC has units of time.

> Find the potential difference across each resistor in Figure P18.31. Figure P18.31:

> For the circuit shown in Figure P18.30, use Kirchhoff’s rules to obtain equations for (a) The upper loop, (b) The lower loop, and (c) The node on the left side. In each case suppress units for clarity and simplify, combining like terms.

> (a) Can the circuit shown in Figure P18.29 be reduced to a single resistor connected to the batteries? Explain. (b) Find the magnitude of the current and its direction in each resistor. Figure P18.29:

> An emf of 10 V is connected to a series RC circuit consisting of a resistor of 2.0 x 106 Ω and an initially uncharged capacitor of 3.0 μF. Find the time required for the charge on the capacitor to reach 90% of its final value.

> A dead battery is charged by connecting it to the live battery of another car with jumper cables (Fig. P18.28). Determine the current in (a) The starter and in (b) The dead battery. Figure P18.28:

> (a) Can the circuit shown in Figure P18.27 be reduced to a single resistor connected to the batteries? Explain. (b) Calculate each of the unknown currents I1, I2, and I3 for the circuit. Figure P18.27:

> Figure P18.26 shows a voltage divider, a circuit used to obtain a desired voltage ΔVout from a source voltage ε. Determine the required value of R2 if ε = 5.00 V, ΔVout = 1.50 V, and R1 = 1.00 x 103 &Icir

> Using Kirchhoff’s rules, (a) Find the current in each resistor shown in Figure P18.25 and (b) Find the potential difference between points c and f. Figure P18.25:

> Four resistors are connected to a battery with a terminal voltage of 12 V, as shown in Figure P18.24. (a) How would you reduce the circuit to an equivalent single resistor connected to the battery? Use this procedure to find the equivalent resistance of

> In the circuit of Figure P18.23, determine (a) The current in each resistor, (b) The potential difference across the 2.00 x 102 - Ω resistor, and (c) The power delivered by each battery. Figure P18.23:

> In the circuit of Figure P18.22, the current I1 is 3.0 A and the values of ε and R are unknown. What are the currents I2 and I3? Figure P18.22:

> Taking R = 1.00 kΩ and ε = 250. V in Figure P18.21, determine the direction and magnitude of the current in the horizontal wire between a and e. Figure P18.21:

> Figure P18.19 shows a Wheatstone bridge, a circuit used to precisely measure an unknown resistance R by varying Rvar until the ammeter reads zero current and the bridge is said to be “balanced.” If the bridge is balanc

> The circuit in Figure P18.55 has been connected for several seconds. Find the current (a) In the 4.00 - V battery, (b) In the 3.00 - Ω resistor, (c) In the 8.00 - V battery, and (d) In the 3.00 - V battery. (e) Find the charge on the capacito

> (a) Find the current in each resistor of Figure P18.18 by using the rules for resistors in series and parallel. (b) Write three independent equations for the three currents using Kirchhoff’s laws: one with the node rule; a second using

> (a) You need a 45 - Ω resistor, but the stockroom has only 20. - Ω and 50. - Ω resistors. How can the desired resistance be achieved under these circumstances? (b) What can you do if you need a 35 - Ω resistor?

> (a) Is it possible to reduce the circuit shown in Figure P18.16 to a single equivalent resistor connected across the battery? Explain. (b) Find the current in the 2.00 - Ω resistor. (c) Calculate the power delivered by the battery to the circ

> Find the current in the 12 - Ω resistor in Figure P18.15. Figure P18.15:

> A 2.00 - nF capacitor with an initial charge of 5.10 μC is discharged through a 1.30 – kΩ resistor. (a) Calculate the magnitude of the current in the resistor 9.00 μs after the resistor is connected across the terminals of the capacitor. (b) What charge

> The given pair of capacitors in Figure P18.67 is fully charged by a 12.0 - V battery. The battery is disconnected and the circuit closed. After 1.00 ms, how much charge remains on (a) The 3.00 - μF capacitor? (b) The 2.00 - μF

> Consider the two arrangements of batteries and bulbs shown in Figure P18.66. The two bulbs are identical and have resistance R, and the two batteries are identical with output voltage ΔV. (a) In case 1, with the two bulbs in series, compare t

> What are the expected readings of the ammeter and voltmeter for the circuit in Figure P18.65? Figure P18.65:

> In Figure P18.64, R1 = 0.100 Ω, R2 = 1.00 Ω, and R3 = 10.0 Ω. Find the equivalent resistance of the circuit and the current in each resistor when a 5.00 - V power supply is connected between (a) Points A and B, (b) Poi

> An electric eel generates electric currents through its highly specialized Hunter’s organ, in which thousands of disk - shaped cells called electrocytes are lined up in series, very much in the same way batteries are lined up inside a flashlight. When ac

> The resistance between points a and b in Figure P18.54 drops to one - half its original value when switch S is closed. Determine the value of R. Figure P18.54:

> Three liquids are at temperatures of 10°C, 20°C, and 30°C, respectively. Equal masses of the first two liquids are mixed, and the equilibrium temperature is 17°C. Equal masses of the second and third are then mixed, and the equilibrium temperature is 28°

> An automobile has a mass of 1500 kg, and its aluminum brakes have an overall mass of 6.00 kg. (a) Assuming all the internal energy transformed by friction when the car stops is deposited in the brakes and neglecting energy transfer, how many times could

> An iron plate is held against an iron wheel so that a sliding frictional force of 50. N acts between the two pieces of metal. The relative speed at which the two surfaces slide over each other is 40. m/s. (a) Calculate the rate at which mechanical energy

> A bar of gold (Au) is in thermal contact with a bar of silver (Ag) of the same length and area (Fig. P11.63). One end of the compound bar is maintained at 80.0°C, and the opposite end is at 30.0°C. Find the temperature at the juncti

> A class of 10 students taking an exam has a power output per student of about 200 W. Assume the initial temperature of the room is 20°C and that its dimensions are 6.0 m by 15.0 m by 3.0 m. What is the temperature of the room at the end of 1.0 h if all t

> Liquid helium has a very low boiling point, 4.2 K, as well as a very low latent heat of vaporization, 2.00 x 104 J/kg. If energy is transferred to a container of liquid helium at the boiling point from an immersed electric heater at a rate of 10.0 W, how

> Overall, 80% of the energy used by the body must be eliminated as excess thermal energy and needs to be dissipated. The mechanisms of elimination are radiation, evaporation of sweat (2430 kJ/kg), evaporation from the lungs (38 kJ/h), conduction, and conv

> The temperature of a silver bar rises by 10.0°C when it absorbs 1.23 kJ of energy by heat. The mass of the bar is 525 g. Determine the specific heat of silver from these data.

> A student measures the following data in a calorimetry experiment designed to determine the specific heat of aluminum: Initial temperature of water and calorimeter: 70.0°C Mass of water: 0.400 kg Mass of calorimeter: 0.040 kg Specific heat of

> The surface area of an unclothed person is 1.50 m2, and his skin temperature is 33.0°C. The person is located in a dark room with a temperature of 20.0°C, and the emissivity of the skin is e = 0.95. (a) At what rate is energy radiated by the body? (b) Wh

> In an analogy between traffic flow and electrical current, (a) What would correspond to the charge Q? (b) What would correspond to the current I?

> A 0.040.-kg ice cube floats in 0.200 kg of water in a 0.100-kg copper cup; all are at a temperature of 0°C. A piece of lead at 98°C is dropped into the cup, and the final equilibrium temperature is 12°C. What is the mass of the lead?

> A family comes home from a long vacation with laundry to do and showers to take. The water heater has been turned off during the vacation. If the heater has a capacity of 50.0 gallons and a 4800-W heating element, how much time is required to raise the t

> The bottom of a copper kettle has a 10.0-cm radius and is 2.00 mm thick. The temperature of the outside surface is 102°C, and the water inside the kettle is boiling at 1 atm of pressure. Find the rate at which energy is being transferred through the bott

> The filament of a 75-W light bulb is at a temperature of 3300 K. Assuming the filament has an emissivity e = 1.0, find its surface area.

> Measurements on two stars indicate that Star X has a surface temperature of 5727°C and Star Y has a surface temperature of 11727°C. If both stars have the same radius, what is the ratio of the luminosity (total power output) of Star Y to the luminosity o

> A granite ball of radius 2.00 m and emissivity 0.450 is heated to 135°C. (a) Convert the given temperature to Kelvin. (b) What is the surface area of the ball? (c) If the ambient temperature is 25.0°C, what net power does the ball radiate?

> A rectangular glass window pane on a house has a width of 1.0 m, a height of 2.0 m, and a thickness of 0.40 cm. Find the energy transferred through the window by conduction in 12 hours on a day when the inside temperature of the house is 22°C and the out

> A Styrofoam box has a surface area of 0.80 m2 and a wall thickness of 2.0 cm. The temperature of the inner surface is 5.0°C, and the outside temperature is 25°C. If it takes 8.0 h for 5.0 kg of ice to melt in the container, determine the thermal conducti

> A person’s basal metabolic rate (BMR) is the rate at which energy is expended while resting in a neutrally temperate environment. A typical BMR is 7.00 x 106 J/day. Convert this BMR to units of (a) Watts and (b) Kilocalories (or Calories) per hour. (c) S

> A copper rod and an aluminum rod of equal diameter are joined end to end in good thermal contact. The temperature of the free end of the copper rod is held constant at 100.°C and that of the far end of the aluminum rod is held at 0°C. If the copper rod i

> A 12 - V battery is connected across a device with variable resistance. As the resistance of the device increases, determine whether the following quantities increase, decrease, or remain unchanged. Indicate your answers with I, D, or U, respectively. (a

> A thermopane window consists of two glass panes, each 0.50 cm thick, with a 1.0-cm-thick sealed layer of air in between. (a) If the inside surface temperature is 23°C and the outside surface temperature is 0.0°C, determine the rate of energy transfer thr

> Consider two cooking pots of the same dimensions, each containing the same amount of water at the same initial temperature. The bottom of the first pot is made of copper, while the bottom of the second pot is made of aluminum. Both pots are placed on a h

> The average thermal conductivity of the walls (including windows) and roof of a house in Figure P11.46 is 4.8 x 10-4 kW/m · °C, and their average thickness is 21.0 cm. The house is heated with natural gas, with a heat of combusti

> A steam pipe is covered with 1.50-cm-thick insulating material of thermal conductivity 0.200 cal/cm · °C · s. How much energy is lost every second when the steam is at 200.°C and the surrounding air is at 20.0 °C? The pipe has a circumference of 800. cm

> The thermal conductivities of human tissues vary greatly. Fat and skin have conductivities of about 0.20 W/m · K and 0.020 W/m · K, respectively, while other tissues inside the body have conductivities of about 0.50 W/m · K. Assume that between the core

> A pond with a flat bottom has a surface area of 820 m2 and a depth of 2.0 m. On a warm day, the surface water is at a temperature of 25°C, while the bottom of the pond is at 12°C. Find the rate at which energy is transferred by conduction from the surfac

> A glass windowpane in a home is 0.62 cm thick and has dimensions of 1.0 m x 2.0 m. On a certain day, the indoor temperature is 25°C and the outdoor temperature is 0°C. (a) What is the rate at which energy is transferred by heat through the glass? (b) How

> The plates of a capacitor are connected to a battery. (a) What happens to the charge on the plates if the connecting wires are removed from the battery? (b) What happens to the charge if the wires are removed from the battery and connected to each other?

> If you are given three different capacitors C1, C2, and C3, how many different combinations of capacitance can you produce, using all capacitors in your circuits?

> Consider point A in Figure CQ15.8 located an arbitrary distance from two point charges in otherwise empty space. (a) Is it possible for an electric field to exist at point A in empty space? (b) Does charge exist at this point? (c) Does a force exist at t

> If a suspended object A is attracted to a charged object B, can we conclude that A is charged? Explain.

> A 3.00-g lead bullet at 30.0°C is fired at a speed of 2.40 x 102 m/s into a large, fixed block of ice at 0°C, in which it becomes embedded. (a) Describe the energy transformations that occur as the bullet is cooled. What is the final temperature of the b

> Two uncharged, conducting spheres are separated by a distance d. When charge -Q is moved from sphere A to sphere B, the Coulomb force between them has magnitude F0. (a) Is the Coulomb force attractive or repulsive? (b) If an additional charge -Q is moved

> The fundamental charge is e = 1.60 x 10-19 C. Identify whether each of the following statements is true or false. (a) It’s possible to transfer electric charge to an object so that its net electric charge is 7.5 times the fundamental electric charge, e.

> A student who grew up in a tropical country and is studying in the United States may have no experience with static electricity sparks and shocks until his or her first American winter. Explain.

> A spherical surface surrounds a point charge q. Describe what happens to the total flux through the surface if (a) The charge is tripled, (b) The volume of the sphere is doubled, (c) The surface is changed to a cube, (d) The charge is moved to another lo