A solid metal cylinder of mass m rolls down parallel metal rails spaced a distance L apart with a constant acceleration of magnitude a0 [part (a) of figure]. The rails are inclined at an angle θ to the horizontal. Now the rails are connected electrically at the top and immersed in a magnetic field of magnitude B that is perpendicular to the plane of the rails [part (b) of figure].
(a) As it rolls down the rails, in what direction does current flow in the cylinder?
(b) What direction is the magnetic force on the cylinder?
(c) Instead of rolling at constant acceleration, the cylinder now approaches a terminal speed vt. What is vt in terms of L, m, R, g, θ, and B? R is the total electrical resistance of the circuit consisting of the cylinder, rails, and wire; assume R is constant (i.e., the resistances of the rails themselves are negligible).
> A square loop of wire of side 2.3 cm and electrical resistance 79 Ω is near a long straight wire that carries a current of 6.8 A in the direction indicated. The long wire and loop both lie in the plane of the page. The left side of the loop i
> The central bright fringe in a single-slit diffraction pattern from light of wavelength 476 nm is 2.0 cm wide on a screen that is 1.05 m from the slit. (a) How wide is the slit? (b) How wide are the first two bright fringes on either side of the centra
> What is the ground-state electron configuration of tellurium (Te, atomic number 52)?
> A circular conducting coil with radius 2.6 cm is placed in a vertical magnetic field of 0.33 T. The coil is made of copper wire with a diameter of 0.90 mm. The coil starts in a horizontal plane and is flipped over (rotated 180° about a horizontal axis) i
> A grating spectrometer is used to resolve wavelengths 660.0 nm and 661.4 nm in second order. (a) How many slits per centimeter must the grating have to produce both wavelengths in second order? (The answer is either a maximum or a minimum number of slit
> In the past, bicycles used small bottle-shaped dc generators to power the headlight. A small wheel (the top of the “bottle”) in contact with a tire caused the shaft of the generator to rotate. Suppose the generator has 150 turns of wire in a circular coi
> A grating 1.600 cm wide has exactly 12000 slits. The grating is used to resolve two nearly equal wavelengths in a light source: λa = 440.000 nm and λb = 440.936 nm. (a) How many orders of the lines can be seen with the grating? (b) What is the angular
> A square loop of wire is made up of 50 turns of wire, 45 cm on each side. The loop is immersed in a 1.4 T magnetic field perpendicular to the plane of the loop. The loop of wire has little resistance but it is connected to two resistors in parallel as sh
> White light containing wavelengths from 400 nm to 700 nm is shone through a grating. Assuming that at least part of the third-order spectrum is present, show that the second- and third-order spectra always overlap, regardless of the slit separation of th
> Compare the electric energy that can be stored in a capacitor to the magnetic energy that can be stored in an inductor of the same size (i.e., the same volume). For the capacitor, assume that air is between the plates; the maximum electric field is then
> A spectrometer is used to analyze a light source. The screen-to- grating distance is 50.0 cm, and the grating has 5000.0 slits/cm. Spectral lines are observed at the following angles: 12.98°, 19.0°, 26.7°, 40.6°, 42.4°, 63.9°, and 77.6°. (a) How many di
> A 15.0 g conducting rod of length 1.30 m is free to slide downward between two vertical rails without friction. The ends of the rod maintain electrical contact with the rails. The rails are connected to an 8.00 Ω resistor, and the entire appa
> A reflection grating spectrometer is used to view the spectrum of light from a helium discharge tube. The three brightest spectral lines seen are red, yellow, and blue in color. These lines appear at the positions labeled A, B, and C in the figure, thoug
> A suspension bridge is 60.0 m above the level base of a gorge. A stone is thrown or dropped from the bridge. Ignore air resistance. At the location of the bridge g has been measured to be 9.83 m/s2. (a) If you drop the stone, how long does it take for it
> An ideal solenoid (N1 turns, length ℓ1, radius r1) is placed inside another ideal solenoid (N2 turns, length ℓ2 > ℓ1, radius r2 > r1) such that the axes of the two coincide. If the current in the outer solenoid is changing at a rate ΔI2/Δt, what is the m
> A grating is made of exactly 8000 slits; the slit spacing is 1.50 µm. Light of wavelength 0.600 µm is incident normally on the grating. (a) How many maxima are seen in the pattern on the screen? (b) Sketch the pattern that would appear on a screen 3.0
> An ideal inductor of inductance L is connected to an ac power supply, which provides an emf ℰ(t) = ℰm sin ωt. (a) Write an expression for the current in the inductor as a function of time. (b) What is the ratio of the maximum emf to the maximum current
> A grating has 5000.0 slits/cm. How many orders of violet light of wavelength 412 nm can be observed with this grating?
> The magnetic field between the poles of an electromagnet is 2.6 T. A coil of wire is placed in this region so that the field is parallel to the axis of the coil. The coil has electrical resistance 25 Φ and radius 1.8 cm. When the current supply to the el
> Red light of 650 nm appears in orders 1, 2 and 3 using a particular grating. What are the minimum and maximum possible number of slits per centimeter in this grating?
> A bar magnet is initially far from a circular loop of wire. The magnet is moved at constant speed along the axis of the loop. It moves toward the loop, proceeds to pass through it, and then continues until it is far away on the right side of the loop. Sk
> A red line (wavelength 630 nm) in the third order overlaps with a blue line in the fourth order for a particular grating. What is the wavelength of the blue line?
> A 50 turn coil with a radius of 10.0 cm is mounted so the coil’s axis can be oriented in any horizontal direction. Initially the axis is oriented so the magnetic flux from Earth’s field is maximized. If the coil’s axis is rotated through 90.0° in 0.080 s
> A refracting telescope is 45.0 cm long, and the caption states that the telescope magnifies images by a factor of 30.0. Assuming these numbers are for viewing an object an infinite distance away with minimum eyestrain, what is the focal length of each of
> An electron is confined in a one-dimensional box of length L. Another electron is confined in a box of length 2L. Both are in the ground state. What is the ratio of their energies E2L/EL?
> A flip coil is a device used to measure a magnetic field. A coil of radius r, N turns, and electrical resistance R is initially perpendicular to a magnetic field of magnitude B. The coil is connected to a special kind of galvanometer that measures the to
> You have a set of converging lenses with focal lengths 1.00 cm, 10.0 cm, 50.0 cm, and 80.0 cm. (a) Which two lenses would you select to make a telescope with the largest magnifying power? What is the angular magnification of the telescope when viewing a
> A CRT requires a 20.0 kV amplitude power supply. (a) What is the turns ratio of the transformer that raises the 170 V amplitude household voltage to 20.0 kV? (b) If the tube draws 82 W of power, find the currents in the primary and secondary windings.
> What is the distance between the objective and eyepiece in the Yerkes telescope? (See Example 24.8.)
> The outside of an ideal solenoid (N1 turns, length ℓ, radius r) is wound with a coil of wire with N2 turns. If the current in the solenoid is changing at a rate ΔI1/Δt, what is the magnitude of the induced emf in the coil?
> Five telescopes all have the same magnifying power. Given the focal length of the objective, rank them in order of the focal length of the eyepiece, greatest to smallest. (a) fo = 80 cm; (b) fo = 60 cm; (c) fo = 100 cm; (d) fo = 50 cm; (e) fo = 120
> The largest constant magnetic field achieved in the laboratory is about 40 T. (a) What is the magnetic energy density due to this field? (b) What magnitude electric field would have an equal energy density?
> A biologist observes a Paramecium with a microscope whose eyepiece and objective have focal lengths 2.25 cm and 1.10 cm, respectively. The specimen is 1.18 cm from the objective lens, and the final image is located at infinity. (a) What is the distance
> How much energy due to Earth’s magnetic field is present in 1.0 m3 of space near Earth’s surface at a place where the field has magnitude 0.045 mT?
> The figure shows a schematic diagram of a microscope. (Note that the image formed by the eyepiece is not at infinity.) For the object and image locations shown, which of the points (A, B, C, or D) represents a focal point of the eyepiece? Draw a ray diag
> Carlos and Shannon are sledding down a snow-covered slope that is angled at 12° below the horizontal. When sliding on snow, Carlos's sled has a coefficient of friction μk = 0.10; Shannon has a “supersled” with μk = 0.010. Carlos takes off down the slope
> A solenoid is 8.5 cm long, 1.6 cm in diameter, and has 350 turns. When the current through the solenoid is 65 mA, what is the magnetic flux through one turn of the solenoid?
> To study the physical features of Hydra viridis, a student uses a compound microscope with a magnifying power of 425. (a) If the eyepiece has focal length 1.9 cm and the tube length is 19.2 cm, what focal length does the objective have? Assume a near po
> A uniform magnetic field of magnitude 0.29 T makes an angle of 13° with the plane of a circular loop of wire. The loop has radius 1.85 cm. What is the magnetic flux through the loop?
> The wing of an insect is 1.0 mm long. When viewed through a microscope, the image is 1.0 m long and is located 5.0 m away. Determine the angular magnification.
> Suppose you wanted to use Earth’s magnetic field to make an ac generator at a location where the magnitude of the field is 0.050 mT. Your coil has 1000.0 turns and a radius of 5.0 cm. At what angular velocity would you have to rotate it in order to gener
> Jordan is building a compound microscope using an eyepiece with a focal length of 7.50 cm and an objective with a focal length of 1.500 cm. He will place the specimen a distance of 1.600 cm from the objective. (a) How far apart should Jordan place the l
> A toroid has a square cross section of side a. The toroid has N turns and radius R. The toroid is narrow (a ≪ R) so that the magnetic field inside the t oroid can be considered to be uniform in magnitude. What is the self-inductance of
> The eyepiece of a microscope has a focal length of 1.25 cm, and the objective lens focal length is 1.44 cm. (a) If the tube length is 18.0 cm, what is the angular magnification of the microscope? (b) What objective focal length would be required to dou
> The strings of an electric guitar are made of ferromagnetic metal. The pickup consists of two components. A magnet causes the part of the string near it to be magnetized. The vibrations of the string near the pickup coil produce an induced emf in the coi
> Five microscopes all have 16 cm tube lengths. Given the focal lengths of the eyepiece and objective, rank them in order of the magnifying power |M|, greatest to smallest. (a) fe = 1.5 cm, fo = 1.5 cm; (b) fe = 2.0 cm, fo = 2.0 cm; (c) fe = 1.5 cm, fo
> A double-slit interference experiment is performed with 2.0 eV photons. The same pair of slits is then used for an experiment with electrons. What is the kinetic energy of the electrons if the spacing between maxima is the same?
> A circular metal ring is suspended above a solenoid. The magnetic field due to the solenoid is shown. The current in the solenoid is increasing. (a) What is the direction of the current in the ring? (b) The flux through the ring is proportional to the
> A simple magnifier gives the maximum angular magnification when it forms a virtual image at the near point of the eye instead of at infinity. For simplicity, assume that the magnifier is right up against the eye, so that distances from the magnifier are
> A biology professor notices a speck on a student's lab report and pulls out her magnifying lens to investigate. Holding the lens close to her eye, she is surprised to find Pelomyxa palustris, the largest known species of amoeba. (a) When observed withou
> If the magnetic force due to Earth's field were the only force on the ion, what would the smallest possible radius of its trajectory be?
> A magnifying glass can focus sunlight enough to heat up paper or dry grass and start a fire. A magnifying glass with a diameter of 4.0 cm has a focal length of 6.0 cm. (a) Using information found in Appendix B, estimate the size of the image of the Sun
> What is the greatest possible magnetic force on the sodium ion due to Earth's field?
> (a) For a converging lens with a focal length of 3.50 cm, find the object distance that will result in an inverted image with an image distance of 5.00 cm. Use a ray diagram to verify your calculations. (b) Is the image real or virtual? (c) What is the
> Suppose some 238U2+ ions are present in the beam. They have the same mass m as the 238U+ ions but twice the charge (+2e). (a) With what speed do the 238U2+ ions emerge from the accelerating plates, assuming 238U+ ions emerge with speed v? (b) Sketch th
> Starting with Fig. 23.39, perform all the algebraic steps to obtain the mirror equation in the form of Eq. (23-22).
> Find the point of no return for an airport runway of 1.50 mi in length if a jet plane can speed up at 10.0 ft/s2 and slow down at 7.00 ft/s2. The point of no return is the point where the pilot can no longer abort the takeoff without running out of runwa
> Find the mass of the 238U+ ions in terms of v, B, D, and universal constants.
> Show that when rays parallel to the principal axis reflect from a concave mirror, the reflected rays all pass through the focal point at a distance R/2 from the vertex. Assume that the angles of incidence are small. [Hint: Follow the similar derivation f
> Suppose some 235U+ ions are present in the beam. They have the same charge as the 238U+ ions but a smaller mass (approximately 0.987 37m). (a) With what speed do the 235U+ ions emerge from the accelerating plates, assuming 238U+ ions emerge with speed v
> Derive the magnification equation, m = h′/h = −q/p, for a convex mirror. Draw a ray diagram as part of the solution.
> The uniform magnetic field in the velocity selector is directed out of the page and has magnitude B. (a) What should the magnitude and direction of the electric field in the selector be to allow ions with speed v to pass straight through? (b) Sketch th
> In a subway station, a convex mirror allows the attendant to view activity on the platform. A woman 1.64 m tall is standing 4.5 m from the mirror. The image formed of the woman is 0.500 m tall. (a) What is the radius of curvature of the mirror? (b) The
> The accelerating plates have area A and are a distance d apart. (a) What should the charges on the plates be so the ions emerge at speed v, ignoring their initial kinetic energies? Indicate which plate is positive and which negative. (b) Sketch the ele
> A concave mirror has a radius of curvature of 5.0 m. An object, initially 2.0 m in front of the mirror, is moved back until it is 6.0 m from the mirror. Describe how the image location changes.
> An engineer wants to design a toy racetrack using an electromagnetic rail gun (see Problem 122) to accelerate a car of mass 40 g starting from rest. The horizontal rails are to be 1.0 m long and 2.0 cm apart. The magnetic field in the rail gun is to be 0
> The right-side rearview mirror of Mike's car says that objects in the mirror are closer than they appear. Mike decides to do an experiment to determine the focal length of this mirror. He holds a plane mirror next to the rearview mirror and views an obje
> The neutrons produced in fission reactors have a wide range of kinetic energies. After the neutrons make several collisions with atoms, they give up their excess kinetic energy and are left with the same average kinetic energy as the atoms, which is / .
> A baryon with charge 0 composed of up and/or strange quarks and/or antiquarks.
> Explain how these quantities differ: distance traveled, displacement, and displacement magnitude.
> Reconsider Prob. 9–162. Using appropriate software, investigate the effect of varying the compressor isentropic efficiency over the range 60 to 100 percent. Plot the power input to the compressor and the electric power saved by using a heat pump rather t
> A heat pump using refrigerant-134a heats a house by using underground water at 8°C as the heat source. The house is losing heat at a rate of 60,000 kJ/h. The refrigerant enters the compressor at 280 kPa and 0°C, and it leaves at 1 MPa and 60°C. The refri
> A pump is used to transport water to a higher reservoir. If the water temperature is 20°C, determine the lowest pressure that can exist in the pump without cavitation.
> A heat pump that operates on the ideal vapor compression cycle with refrigerant-134a is used to heat a house and maintain it at 75°F by using underground water at 50°F as the heat source. The house is losing heat at a rate of 80,000 Btu/h. The evaporator
> The pressure on the suction side of pumps is typically low, and the surfaces on that side of the pump are susceptible to cavitation, especially at high fluid temperatures. If the minimum pressure on the suction side of a water pump is 0.70 psia absolute,
> Refrigerant-134a enters the condenser of a residential heat pump at 800 kPa and 50°C at a rate of 0.022 kg/s and leaves at 750 kPa subcooled by 3°C. The refrigerant enters the compressor at 200 kPa superheated by 4°C. Det
> What is cavitation? What causes it?
> An air-standard cycle with variable specific heats is executed in a closed system and is composed of the following four processes: 1-2 v = constant heat addition from 14.7 psia and 80°F in the amount of 300 Btu/lbm 2-3 P = constant heat addition to 3200
> Define internal, external, and open-channel flows.
> A heat pump operates on the ideal vapor-compression refrigeration cycle and uses refrigerant 134a as the working fluid. The condenser operates at 1000 kPa and the evaporator at 200 kPa. Determine this system’s COP and the rate of heat supplied to the eva
> The temperature of the lubricating oil in an automobile engine is measured as 150°F. What is the temperature of this oil in °C?
> What is a water-source heat pump? How does the COP of a water-source heat pump system compare to that of an air-source system?
> Do you think a heat pump system will be more cost-effective in New York or in Miami? Why?
> An actual refrigerator operates on the vapor-compression refrigeration cycle with refrigerant-22 as the working fluid. The refrigerant evaporates at −15°C and condenses at 40°C. The isentropic efficiency of the compressor is 83 percent. The refrigerant i
> The manufacturer of an air conditioner claims a seasonal energy efficiency ratio (SEER) of 16 (Btu/h)/W for one of its units. This unit operates on the normal vapor-compression refrigeration cycle and uses refrigerant-22 as the working fluid. This SEER i
> A commercial refrigerator with refrigerant-134a as the working fluid is used to keep the refrigerated space at −30°C by rejecting its waste heat to cooling water that enters the condenser at 18°C at a rate of 0.25
> A refrigerator uses refrigerant-134a as the working fluid and operates on the vapor-compression refrigeration cycle. The evaporator and condenser pressures are 200 kPa and 1400 kPa, respectively. The isentropic efficiency of the compressor is 88 percent.
> Repeat Prob. 9–151E using appropriate software if ammonia is used in place of refrigerant-134a. Data from Prob. 9-151: A refrigerator uses refrigerant-134a as its working fluid and operates on the ideal vapor compression refrigeration cycle. The refrige
> A refrigerator uses refrigerant-134a as its working fluid and operates on the ideal vapor compression refrigeration cycle. The refrigerant evaporates at 5°F and condenses at 180 psia. This unit serves a 45,000 Btu/h cooling load. Determine the mass flow
> An ideal vapor-compression refrigeration cycle that uses refrigerant-134a as its working fluid maintains a condenser at 800 kPa and the evaporator at −20°C. Determine this system’s COP and the amount of powe
> Repeat Prob. 9–14 using constant specific heats at room Temperature. Data from Prob. 9-14: An air-standard cycle with variable specific heats is executed in a closed system with 0.003 kg of air and consists of the following three processes: 1-2 v = cons
> The temperature of a system drops by 45°F during a cooling process. Express this drop in temperature in K, R, and °C.
> A refrigerator uses refrigerant-134a as the working fluid and operates on the ideal vapor compression refrigeration cycle except for the compression process. The refrigerant enters the evaporator at 120 kPa with a quality of 34 percent and leaves the com
> A refrigerator operates on the ideal vapor-compression refrigeration cycle and uses refrigerant 134a as the working fluid. The condenser operates at 300 psia and the evaporator at 20°F. If an adiabatic, reversible expansion device were available and used
> An ideal vapor-compression refrigeration cycle using refrigerant-134a as the working fluid is used to cool a brine solution to −5°C. This solution is pumped to various buildings for the purpose of air conditioning. The refrigerant evaporates at −10°C wit
> An air conditioner using refrigerant-134a as the working fluid and operating on the ideal vapor compression refrigeration cycle is to maintain a space at 22°C while operating its condenser at 1000 kPa. Determine the COP of the system when a temperature d
> An ice-making machine operates on the ideal vapor-compression cycle, using refrigerant-134a. The refrigerant enters the compressor as saturated vapor at 20 psia and leaves the condenser as saturated liquid at 80 psia. Water enters the ice machine at 55°F
> A 10-kW cooling load is to be served by operating an ideal vapor-compression refrigeration cycle with its evaporator at 400 kPa and its condenser at 800 kPa. Calculate the refrigerant mass flow rate and the compressor power requirement when refrigerant-1
> The COP of vapor-compression refrigeration cycles improves when the refrigerant is subcooled before it enters the throttling valve. Can the refrigerant be subcooled indefinitely to maximize this effect, or is there a lower limit? Explain.
> It is proposed to use water instead of refrigerant-134a as the working fluid in air-conditioning applications where the minimum temperature never falls below the freezing point. Would you support this proposal? Explain.