Inquiry into Physics 8th edition Vern J. Ostdiek, Donald J. Bord - Solutions

Describe the wave forms of pure tones, complex tones, and noise.
What is ultrasound? Give two examples of what it can be used for.
The frequency of the highest note on the piano is 4,186 Hz. (a) How many harmonics of that note can we hear? (b) How many harmonics of the note one octave below it can we hear?
Describe how sound is produced in string instruments. Why does tightening a string change the frequency of the sound it makes?
A conditioning drill consists of repeatedly running from one end of a basketball court to the other, turning around and running back. Sometimes the drill is changed and the runner turns around at half court, or perhaps at three-fourths of the length of the court. Describe how the number of
What is reverberation? How does reverberation affect how we hear sounds?
What are the three categories used to describe our mental perception of a sound? On what physical properties of sound waves does each depend?
A 100-Hz pure tone at a 70-dB sound level and a 1,000-Hz pure tone at the same sound level are heard separately. Do they sound equally loud? If not, which is louder, and why?
A sound is produced by combining three pure tones with frequencies of 200 Hz, 400 Hz, and 600 Hz. A second sound is produced using 200 Hz, 413 Hz, and 600 Hz pure tones. What important difference is there between the two sounds?
The highest musical note on the piano has a frequency of 4,186 Hz. Why would a tape of piano music sound terrible if played on a tape player that reproduces frequencies only up to 5,000 Hz?
Normal telephones do not transmit pure tones with frequencies below about 300 Hz. But a person whose speaking voice has a frequency of 100 Hz can be heard and understood over the phone. Why is that?
A special room contains a mixture of oxygen and helium that is breathable. Two musicians play a guitar and a flute in the room. Does each instrument sound different from when it is played in normal air? Why or why not?
An audio speaker producing a steady sound at an outdoor concert is 25 ft away from you. If you move to a position where the speaker is 75 ft distant, by what factor will the amplitude of the sound change?
Six transverse waves move through different media. They all have the same frequency, but their amplitudes, A, and wavelengths, λ, vary as indicated. Rank these waves according to their propagation speeds, from largest to smallest. That is, rank the wave that is traveling fastest first, and place
Six strings, all having the same lengths, are stretched taut between two fixed points. The tensions, F, and masses, m, of the strings vary as shown. A transverse pulse with a given amplitude is initiated near one end of each of the strings and propagates toward the other end. Rank the speeds of the
A solid metal cylinder has a certain resistance. It is then heated and carefully stretched to form a longer, thinner cylinder. After it cools, will its resistance be the same as, greater than, or less than what it was before? Explain your choice.
An electric train operates on 750 V. What is its power consumption when the current flowing through the train’s motor is 2,000 A?
A student using a sensitive meter that measures resistance finds that the resistance of a thin wire is changed slightly when it is picked up with a bare hand. What causes the change in the resistance, and does it increase or decrease?
If a new material is found that is a superconductor at all temperatures, what parts of some common electric devices would definitely not be made out of it? Explain.
Your cell phone typically consumes about 400 mW of power when you text a friend. If the phone is operated using a lithium-ion battery with a voltage of 3.6 V, what is the current flowing through the cell-phone circuitry under these circumstances? Compare your result with the data given in Table 7.1.
Explain what current, resistance, and voltage are.
Make a sketch of a simple electric circuit and label the key elements in the circuit.
Describe Ohm’s law.
A power supply is connected to two bare wires that are inserted into a glass of saltwater. The resistance of the water decreases as the voltage is increased. Sketch a graph of the voltage versus the current in the water showing this type of behavior.
A clock consumes 2 W of electrical power. How much energy does it use each day?
There are two basic methods for connecting more than one electrical device in a circuit. Name, describe, and give the advantages of each.
Make a sketch of an electric circuit that contains a switch and two lightbulbs connected in such a way that if either bulb burns out the other still functions, but if the switch is turned off, both bulbs go out.
A representative lightning strike is caused by a voltage of 200,000,000 V and consists of a current of 1,000 A that flows for a fraction of a second. Calculate the power.
Two 1.5-volt batteries are connected in series in an electric circuit. Use the concept of energy to explain why this combination is equivalent to a single 3-volt battery. When connected in parallel, what are two 1.5-volt batteries equivalent to?
An electrical supply company sells two models of 100-watt power supplies (the maximum power output is 100 W), one with an output of 12 V and the other 6 V. What can you conclude about the maximum current that the two power supplies can produce?
A certain electric motor draws a current of 10 A when connected to 120 V.(a) What is the motor’s power consumption?(b) How much energy does it use during 4 h of operation? Express the answer in joules and in kilowatt-hours.
A simple electric circuit consists of a constant-voltage power supply and a variable resistor. What effect does reducing the resistance have on the current in the circuit and on the power output of the power supply?
What is the purpose of having fuses or circuit breakers in electric circuits? How should they be connected in circuits so they will be effective?
A lightbulb is rated at 60 W when connected to 120 V.(a) What current flows through the bulb in this case?(b) What is the bulb’s resistance?(c) What would be the current in the bulb if it were connected to 60 V, assuming the resistance stays the same?(d) What would be its power consumption in
A 20-A fuse in a household electric circuit burns out. What catastrophe could occur if it is replaced by a 30-A fuse?
Why is it economical to use extremely high voltages for the transmission of electrical power?
A simple circuit of the form shown in Figure 7.37 is constructed using a battery and three lightbulbs. The bulbs may have different resistances as given in the six circumstances A through F. For each situation, however, the battery in the circuit is always the same, as are the wire connections.
Rank the force on each of the point charges q1 and q2 in the following pairings from most attractive to most repulsive. The separation, d, between each pair is given. Explain the reasoning you used to arrive at your rankings.Pair 1: q1 = + 2 μC; q2 = - 4 μC; and d = 10 cmPair 2: q1 = + 2 μC; q2
Six resistors, all having the same temperatures and compositions, are each attached to a battery with voltage V to form a simple circuit. The resistors have different lengths, l, but the same diameters. Rank the circuits according to the current that flows through the resistor from smallest to
Saltwater contains an equal number of positive and negative ions. When saltwater is flowing through a pipe, does it constitute an electric current?
Materials can be classified into four categories based on the ease with which charges can flow through them. Give the names of these categories and describe each one.
An electric car is being designed to have an average power output of 4,000 W for 2 h before needing to be recharged. (Assume there is no wasted energy.)(a) How much energy would be stored in the charged batteries?(b) The batteries operate on 30 V. What would the current be when they are operating
Explain what AC and DC are. Why is AC used by electric utilities? Why is DC used in flashlights?
If AC in a circuit can be thought of as a wave, which kind is it, longitudinal or transverse?
If the electric utility company where you live suddenly changed the frequency of the AC to 20 Hz, what problems might this cause?
What happens to a ferromagnetic material when it is placed in a magnetic field? What causes magnetic declination? Is there a place where the magnetic declination is 1808 (a compass points south)? If so, approximately where?
A solenoid connected to a 60-Hz AC source will produce an oscillating magnetic field, as we have seen. If a permanent magnet is inserted into the solenoid, it will oscillate, but not with the same frequency that an unmagnetized piece of iron would. Why?
What is the wavelength of the 60,000-Hz radio wave used by “radio-controlled” clocks and wristwatches?
Describe the three basic interactions between electricity and magnetism.
Explain what superconducting electromagnets are. What advantages do they have over conventional electromagnets?
Sketch a diagram of an atom with one electron orbiting the nucleus. Use the right-hand rule to determine the direction of the magnetic field produced by the electron.
The wavelength of an electromagnetic wave is measured to be 600 m.(a) What is the frequency of the wave?(b) What type of EM wave is it?
What disadvantages do they have?
If a coil of wire is connected to a very sensitive ammeter and then waved about in the air, a current will be induced in it even if there are no magnets around. Why?
Name five different basic devices that use at least one of the electromagnetic interactions.
Even though the output voltage of a transformer can be much larger than the input voltage, the power output is nearly the same as the power input. Use this to determine the relationship between the input and output currents and the number of turns in the input and output coils.
A piece of iron is heated with a torch to a temperature of 900 K. How much more energy does it emit as blackbody radiation at 900 K than it does at room temperature, 300 K?
In many cases, the effect of an electromagnetic interaction is perpendicular to its cause. Describe two different examples that illustrate this.
The highest frequency sound that can be recorded by a tape recorder depends on the size of the gap in the recording head. Why? Would a wider or a narrower gap be capable of recording higher frequencies?
To test whether a material is a superconductor, a scientist decides to make a ring out of the material and then to see whether a current will flow around in the ring with no steady energy input.(a) Explain how a magnet could be used to initiate the current.(b) At some later time, how could the
Describe what happens to an electric charge as an electromagnetic wave passes through the region around it. Explain why the charge will produce another electromagnetic wave.
A rectangular metal plate measures 0.15 m long and 0.1 m wide. The plate is heated to a temperature of 1,200 K by passing a current through it. Assuming that it behaves like a blackbody, how much power does the plate radiate under these conditions?
A coil of wire has a large alternating current flowing in it. A piece of aluminum or copper placed near the coil becomes warm even if it does not touch the coil. Explain why.
Would an electromagnetic pump be able to move a liquid superconductor? Why or why not?
The nuclei of carbon atoms that are found in Nature come in two main “varieties” called isotopes. The carbon-14 nuclei have a greater mass than the carbon-12 nuclei. The two types of atoms can be separated from each other by ionizing them, accelerating them all to some uniform velocity, and
In the particular accelerator shown in Figure8.16, what are the possible directions of the magnetic field that keeps the particles traveling around the circular path?
What is the wavelength of the peak of the blackbody radiation curve for the human body (T = 310 K)? What type of EM wave is this?
Explain why a transformer doesn’t work with DC.
What is the frequency of the EM wave emitted most strongly by a glowing element on a stove with temperature 1,500 K?
What would an audio speaker like that shown in Figure8.23 do at the instant a low-voltage battery is connected to it? N N Voice coil AC in S S Speaker cone (a) Sound
What is the lowest temperature that will cause a black body to emit radiation that peaks in the infrared?
What is analog-to-digital conversion and how is it used in sound reproduction?
Explain how electromagnetic waves are a natural outcome of the principles of electromagnetism.
An electromagnetic wave travels in a region of space occupied only by a free electron. Describe the resulting motion of the electron.
List the main types of electromagnetic waves in order of increasing frequency. Give at least one useful application for each type of wave.
Alternating current with a frequency of 1 million Hz flows in a wire. What in particular could be detected traveling outward from the wire?
Aircraft equipped with powerful radar units are forbidden from using them when parked on the ground near people. Explain why this is so.
What is different about our perceptions of the different frequencies within the visible light band of the EM spectrum?
Which type of EM wave does your body emit most strongly?
A heat lamp is designed to keep food and other things warm. Would it also make a good tanning lamp? Why or why not?
How are x-rays produced?
Why are x-rays more strongly absorbed by bones than by muscles and other tissues?
What is blackbody radiation? In what ways does the radiation emitted by a blackbody change as its temperature increases?
A liquid compound is not heated by microwaves the way water is. What can you conclude about the nature of the compound’s molecules?
What are the main uses of microwaves? Explain how each process works.
What is the “motor-generator duality”? Explain how it is used.
Referring to the lightbulbs described in Question 30 and assuming the emitting areas of the filaments in the two bulbs are the same, which of the two is the brighter? About how much brighter is this bulb than its companion?Data from Question 30A lightbulb manufacturer makes bulbs with different
A lightbulb manufacturer makes bulbs with different “color temperatures,” meaning that the spectrum of light they emit is similar to a blackbody with that temperature. What would be the difference in appearance of the light from bulbs with color temperatures of 2,000 K and 4,000 K?
Explain how infrared light can be used to detect some types of animals in the dark. Can you think of a situation in which this would not work?
What effect does the ozone layer have on the EM waves from the Sun? What is currently threatening the ozone layer?
Describe the greenhouse effect that is occurring in Earth’s atmosphere.
How does the ionosphere affect the range of radio communications?
Five transformers, all with the same basic construction (Figure 8.52), have different numbers of turns of wire as their input, N in , and output, Nout, coils according to the circumstances given below. The input voltages, V in , for the five transformers also vary as indicated. Rank the output
Six blackbody radiators have temperatures and emitted powers as given. Rank these blackbodies according to their emitting surface areas from smallest to largest. Justify your rankings based on your knowledge of the physics of blackbodies.Blackbody A: P = 6000 W; T = 50 KBlackbody B: P = 6000 W; T =
A camera is equipped with a telephoto lens that has a focal length of 200 mm. Repeat part (c) of Challenge 8 for this situation.Repeat part (c) of Challenge 8 (c) The kitten is then photographed from a distance of 3,500 mm (11.5 ft). Compute the lens-to-film distance, the magnification, and the
How would Figure 9.29a be different if the glass were replaced by water or by diamond? (a) Partial reflection Air Glass
Of the three converging lenses shown in Figure 9.44, which would you expect to have the shortest focal length? Why? Converging Diverging Converging Diverging Converging Diverging DI JL (( (a) (b) (c)
Referring to Figure 9.64, why doesn’t the ray inside each of the two prisms get refracted out of the prisms at the second interface instead of turned back into the glass? Similarly, referring to Figure 9.17, why don’t the rays that undergo two reflections inside the pentaprism get refracted out
It is determined by immersing a crown in water that its volume is 26 in.3 5 0.015 ft3.(a) What would its weight be if it were made of pure gold?(b) What would its weight be if its volume were half gold and half lead?
It is easier for a person to float in the ocean than in an ordinary swimming pool. Why?

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Inquiry into Physics 8th edition Vern J. Ostdiek, Donald J. Bord - Solutions

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