College Physics
1st Edition
ISBN: 9781938168000
Author: Paul Peter Urone, Roger Hinrichs
Publisher: OpenStax College
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Textbook Question
Chapter 23, Problem 42PE
The motor in a toy car operates on 6.00 V. developing a 4.50 V back emf at normal speed. If it draws 3.00 A at normal speed, what current does it draw when starting?
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A current of 5.75 A flows in the coil of wire from an applied voltage of 120 V. The motor operates at a normal speed and creates a back emf of 32.0 V. What is the resistance of the coil?
Suppose a motor connected to a 117 V source draws 20.2 A when it first starts.
(a) What is its resistance?
(b) What current does it draw at its normal operating speed when it develops a 100 V back emf?
(c) The motor in a toy car operates on 6.20 V, developing a 3.00 v back emf at normal speed. If it draws 2.80 A at normal speed, what current does it draw when starting?
A
A dc motor with its rotor and field coils connected in serieshas an internal resistance of 3.2 Ω. When the motor is running at fullload on a 120 V line, the emf in the rotor is 105 V. What is the current drawn by the motor from the line?
Chapter 23 Solutions
College Physics
Ch. 23 - How do the multiple-loop coils and iron ring in...Ch. 23 - When a magnet is thrust into a coil as in Figure...Ch. 23 - Explain how magnetic flux can be zero when the...Ch. 23 - Is an emf induced in the coil in Figure 23.54 when...Ch. 23 - A person who works with large magnets sometimes...Ch. 23 - A particle accelerator sends highvelocity charged...Ch. 23 - Why must pan of the circuit be moving relative to...Ch. 23 - A powerful induction cannon can be made by placing...Ch. 23 - An induction slave heats a pot with a coil...Ch. 23 - Explain how you could thaw out a frozen water pipe...
Ch. 23 - Explain why magnetic damping might not be...Ch. 23 - Explain how electromagnetic induction can be used...Ch. 23 - Using RHR-l, show that the emfs in the sides of...Ch. 23 - The source of a generator’s electrical energy...Ch. 23 - Suppose you find that the belt drive connecting a...Ch. 23 - Explain what causes physical vibrations in...Ch. 23 - Does plastic insulation on live/hot wires prevent...Ch. 23 - Why are ordinary circuit breakers and fuses...Ch. 23 - A GFI may trip just because the live/hot and...Ch. 23 - How would you place two identical flat coils in...Ch. 23 - How would you shape a given length of wire to give...Ch. 23 - €22. Verify, as was concluded without proof in...Ch. 23 - Presbycusis is a hearing loss due to age that...Ch. 23 - Would you use a large inductance or a large...Ch. 23 - High-frequency noise in AC power can damage...Ch. 23 - Does inductance depend on current, frequency, or...Ch. 23 - Explain why the capacitor in Figure 23.55(a) acts...Ch. 23 - If the capacitors in Figure 23.55 are replaced by...Ch. 23 - Does the resonant frequency of an AC circuit...Ch. 23 - Suppose you have a motor with a power factor...Ch. 23 - What is the value of the magnetic flux at coil 2...Ch. 23 - What is the value of the magnetic flux through the...Ch. 23 - Referring to Figure 23.5?(a), what is the...Ch. 23 - Referring to Figure 23.57(b), what is the...Ch. 23 - Referring to Figure 23.58, what are the directions...Ch. 23 - Repeat the previous problem with the battery...Ch. 23 - Verify that the units /t are volts. That is, show...Ch. 23 - Suppose a 50-turn coil lies in the plane of the...Ch. 23 - (a) An MRI technician moves his hand from a region...Ch. 23 - Integrated Concepts Referring to the situation in...Ch. 23 - An emf is induced by rotating a 1000-turn, 20.0 cm...Ch. 23 - A 0.250 m radius, 500-turn coil is rotated...Ch. 23 - Integrated Concepts Approximately how does the emf...Ch. 23 - Integrated Concepts A lightning bolt produces a...Ch. 23 - Use Faraday’s law, Lenz’s law, and RHR—l to show...Ch. 23 - If a current flows in the Satellite Tether shown...Ch. 23 - (a) A jet airplane with a 75.0 m wingspan is...Ch. 23 - (a) A nonferrous screwdriver is being used in a...Ch. 23 - At what speed must the sliding rod in Figure 23.11...Ch. 23 - The 12.0 cm long rod in Figure 23.11 moves at 4.00...Ch. 23 - Prove that when B, l, and v are not mutually...Ch. 23 - In the August 1992 space shuttle flight, only 250...Ch. 23 - Integrated Concepts Derive an expression for the...Ch. 23 - Integrated Concepts The Tethered Satellite in...Ch. 23 - Integrated Concepts The Tethered Satellite...Ch. 23 - Make a drawing similar to Figure 23.14, but with...Ch. 23 - Figure 23.59 A coil is moved into and out of a...Ch. 23 - Calculate the peak voltage of a generator that...Ch. 23 - At what angular velocity in rpm will the peak...Ch. 23 - What is the peak emf generated by rotating a...Ch. 23 - What is the peak emf generated by a 0.250 m...Ch. 23 - (a) A bicycle generator rotates at 1875 rad/s,...Ch. 23 - Integrated Concepts This problem refers to the...Ch. 23 - (a) A car generator turns at 400 rpm when 1he...Ch. 23 - Show that if a coil rotates at an angular velocity...Ch. 23 - A 75-turn, 10.0 cm diameter coil rotates at an...Ch. 23 - (a) If the emf of a coil rotating in a magnetic...Ch. 23 - Unreasonable Results A 500-turn coil with a 0.250...Ch. 23 - Suppose a motor connected to a 120 V source draws...Ch. 23 - A motor operating on 240 V electricity has a 180 V...Ch. 23 - What is the back emf of a 120 V motor that draws...Ch. 23 - The motor in a toy car operates on 6.00 V....Ch. 23 - Integrated Concepts The motor in a toy car is...Ch. 23 - A plug—in transformer, like that in Figure 23.29,...Ch. 23 - An American traveler in New Zealand carries a...Ch. 23 - A cassette recorder uses a plug-in transformer to...Ch. 23 - (a) What is the voltage output of a transformer...Ch. 23 - (a) The plug-in transformer for a laptop computer...Ch. 23 - A multipurpose transformer has a secondary coil...Ch. 23 - A large power plant generates electricity at 12.0...Ch. 23 - If the power output in the previous problem is...Ch. 23 - Unreasonable Results The 335 kV AC electricity...Ch. 23 - Construct Your Own Problem Consider a double...Ch. 23 - Integrated Concepts A short circuit to the...Ch. 23 - Two coils are placed close together in a physics...Ch. 23 - If two coils placed next to one another have a...Ch. 23 - The 4.00 A current through a 7.50 mH inductor is...Ch. 23 - A device is turned on and 3.00 A flows through it...Ch. 23 - Starting with emf2=MI1t, show that the units of...Ch. 23 - Camera flashes charge a capacitor to high voltage...Ch. 23 - A large research solenoid has a self-inductance of...Ch. 23 - (a) Calculate the self-inductance of a 50.0 cm...Ch. 23 - A precision laboratory resistor is made of a coil...Ch. 23 - The healing coils in a hair dryer are 0.800 cm in...Ch. 23 - When the 20.0 A current through an inductor is...Ch. 23 - How fast can the 150 A current through a 0.250 H...Ch. 23 - Integrated Concepts A very large, superconducting...Ch. 23 - Unreasonable Results A 25.0 H inductor has 100 A...Ch. 23 - It you want a characteristic RL time constant of...Ch. 23 - Your RL circuit has a characteristic time constant...Ch. 23 - A large superconducting magnet, used for magnetic...Ch. 23 - Verify that alter a time of 10.0 ms, the current...Ch. 23 - Suppose you have a supply of inductors ranging...Ch. 23 - (a) What is the characteristic time constant of a...Ch. 23 - What percentage of the final current I0 flows...Ch. 23 - The 5.00 A current through a 1.50 H inductor is...Ch. 23 - (a) Use the exact exponential treatment to find...Ch. 23 - (a) Using the exact exponential treatment, find...Ch. 23 - At what frequency will a 30.0 mH inductor have a...Ch. 23 - What value of inductance should be used if a 20.0...Ch. 23 - What capacitance should be used to produce a 2.00...Ch. 23 - At what frequency will an 80.0 mF capacitor have a...Ch. 23 - (a) Find me current through a 0.500 H inductor...Ch. 23 - (a) What current flows when a 60.0 Hz, 480 V AC...Ch. 23 - A 20.0 kHz, 16.0 V source connected to an inductor...Ch. 23 - A 20.0 HZ, 16.0 V source produces a 2.00 mA...Ch. 23 - (a) An inductor designed to filter high-frequency...Ch. 23 - The capacitor in Figure 23.55(a) is designed to...Ch. 23 - The capacitor in Figure 23.55(b) will filler...Ch. 23 - Unreasonable Results In a recording of voltages...Ch. 23 - Construct Your Own Problem Consider the use of an...Ch. 23 - An RL circuit consists of a 40.0 (resistor and a...Ch. 23 - An RC circuit consists of a 40.0 (resistor and a...Ch. 23 - An LC circuit consists of a 3.00 mH inductor and a...Ch. 23 - What is the resonant frequency of a 0.500 mH...Ch. 23 - To receive AM radio, you want an RLC circuit that...Ch. 23 - Suppose you have a supply of inductors ranging...Ch. 23 - What capacitance do you need to produce a resonant...Ch. 23 - What inductance do you need to produce a resonant...Ch. 23 - The lowest frequency in the FM radio band is 88.0...Ch. 23 - An RLC series circuit has a 2.50 (resistor, a 100...Ch. 23 - An RLC series circuit hag a 1.00 k(register, a 150...Ch. 23 - An RLC series circuit has a 2.50 (resistor, a 100...Ch. 23 - An RLC series circuit has a 1.00 k(resistor, a...Ch. 23 - An RLC series circuit has a 200 (resistor and a...Ch. 23 - Referring to Example 23.14, find the average power...
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