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How much heat must be removed from a 200-g block of copper to lower its temperature from 150C to 30C? The specific heat capacity of copper is 0.093 cal/gC. How much heat must be added to 60 g of ice at 0C to melt the ice completely? How much heat must be added to 120 g of water at an initial temperature of 60C to a. Heat it to the boiling point? b. Completely convert the 100C water to steam? While a gas does 300 J of work on its surroundings, 800 J of heat is added to the gas. What is the change in the internal energy of the gas? The volume of an ideal gas is increased from 0.8 m 3 to 2.4 m 3 while maintaining a constant pressure of 1000 Pa (1 Pa 1 N/m 2 ). How much work is done by the gas in this expansion? If the initial temperature in exercise E14 is 700K, what is the final temperature? Data from Problem 14 The volume of an ideal gas is increased from 0.8 m 3 to 2.4 m 3 while maintaining a constant... Heat is added to an object initially at 30C, increasing its temperature to 80C. a. What is the temperature change of the object in Fahrenheit degrees? b. What is the temperature change of the object... A heat engine with an efficiency of 25% does 400 J of work in each cycle. How much heat must be supplied from the high-temperature source in each cycle? In one cycle, a heat engine takes in 900 J of heat from a high-temperature reservoir and releases 600 J of heat to a lower-temperature reservoir. a. How much work is done by the engine in each cycle?... A heat engine with an efficiency of 40% takes in 600 J of heat from the high-temperature reservoir in each cycle. a. How much work does the engine do in each cycle? b. How much heat is released to... In one cycle, a heat engine does 400 J of work and releases 500 J of heat to a lower-temperature reservoir. a. How much heat does it take in from the higher temperature reservoir? b. What is the... When two different materials are rubbed together, do the two materials acquire the same type of charge or different types of charge? Explain how you could justify your answer with a simple experiment. Two pith balls are both charged by contact with a plastic rod that has been rubbed by cat fur. a. What sign will the charges on the pith balls have? Explain. b. Will the two pith balls attract or... When a glass rod is rubbed by a nylon cloth, which of these two objects gains electrons? Explain. Two pith balls are charged by touching one to a glass rod that has been rubbed with a nylon cloth and the other to the cloth itself. a. What sign will the charge on each pith ball have? Explain. b.... Do the two metal-foil leaves of an electroscope gain charges of opposite sign when the electroscope is charged? Explain. If you charge an electroscope with a plastic rod that has been rubbed with cat fur, will the metal leaves of the electroscope move farther apart or come closer together when you bring the cat fur... When you comb your hair with a plastic comb, what will the sign be on the charge acquired by the comb? Explain. (Compare this process to rubbing a plastic rod with cat fur.) Describe how Benjamin Franklins single-fluid model can explain what happens when we charge a glass rod by rubbing it with a nylon cloth. How do we get two types of charge from a single fluid? Explain. If you touch the metal ball of a charged electroscope with an uncharged glass rod held in your hand, will the electroscope discharge completely? Explain. If you touch the ball of a charged electroscope with your finger, will it discharge? What does this suggest about the conducting properties of people? Explain. Consider the circuit shown, where the wires are connected to either side of a wooden block as well as to the light bulb. Will the bulb light in this arrangement? Explain. 1.5 V Wood block Q5 Diagram Suppose that one of the two charges in synthesis problem 2 is twice as large as the other one. Use the procedures suggested in parts a and b of synthesis problem 2 for this new situation. (When... Suppose that four equal positive charges are located at the corners of a square, as in the diagram. a. Using small arrows, indicate the direction of the electric field at each of the labeled points.... Consider the circuit shown. Could we increase the brightness of the bulb by connecting a wire between points A and B? Explain. A B Q6 Diagram Two circuit diagrams are shown. Which one, if either, will cause the light bulb to light? Explain your analysis of each case. 1.5 V (a) Q7 Diagram 1.5 V (b) Open switch Suppose that we use an uncoated metal clamp to hold the wires in place in the battery-and-bulb circuit shown. Will this be effective in keeping the bulb burning brightly? Explain. 1.5 V Q8 Diagram Two resistors are connected in series with a battery as shown in the diagram. R 1 is less than R 2 . a. Which of the two resistors, if either, has the greater current flowing through it? Explain. b.... How does a bimetallic strip break a circuit when things heat up? Explain. A charge of 30 C passes at a steady rate through a resistor in a time of 5s. What is the current through the resistor? A current of 2.5 A flows through a battery for 1 min. How much charge passes through the battery in that time? A 24- resistor in a circuit has a voltage difference of 6 V across its leads. What is the current through this resistor? A current of 1.5 A is flowing through a resistance of 18 . What is the voltage difference across this resistance? A current of 0.6 A flows through a resistor with a voltage difference of 120 V across it. What is the resistance of this resistor? Three 20- resistors are connected in series to a 6-V battery of negligible internal resistance. a. What is the current flowing through each resistor? b. What is the voltage difference across each... A 40- resistor and a 60- resistor are connected in series to a 12-V battery. a. What is the current flowing through each resistor? b. What is the voltage difference across each resistor? In the circuit shown, the 1- resistance is the internal resistance of the battery and can be considered to be in series, as shown, with the battery and the 9- load. a. What is the current flowing... Two resistors, each having a resistance of 8 , are connected in parallel. What is the equivalent resistance of this combination? Three resistors of 3 , 6 , and 2 are connected in parallel with one another. What is the equivalent resistance of this combination? A 9-V battery in a simple circuit produces a current of 1.5 A through the circuit. How much power is being delivered by the battery? A 30- resistor has a voltage difference of 3 V across its leads. a. What is the current through the resistor? b. What is the power being dissipated in this resistor? A 60-W light bulb operates on an effective ac voltage of 110 V. a. What is the effective current through the light bulb? b. From Ohms law, what is the resistance of the light bulb? A toaster draws a current of 7 A when it is connected to a 110-V ac line. a. What is the power consumption of this toaster? b. What is the resistance of the heating element in the toaster? Three resistors are connected to a 6-V battery as shown. The internal resistance of the battery is negligible. a. What is the current through the 15- resistance? b. Does this same current flow... Three identical resistances, each 24 , are connected in parallel with one another as shown. The combination is connected to a 12-V battery whose internal resistance is negligible. a. What is the... A clothes dryer uses 5500 W of power when connected to a 220-V ac line. How much current does the dryer draw from the line? A longitudinal wave on a Slinky has a frequency of 5 Hz and a speed of 2.0 m/s. What is the wavelength of this wave? A wave on a rope is shown in the diagram. a. What is the wavelength of this wave? b. If the frequency of the wave is 2 Hz, what is the wave speed? 6 m E4 Diagram A wave on a string has a speed of 12 m/s and a period of 0.4 s. a. What is the frequency of the wave? b. What is the wavelength of the wave? Suppose that a guitar string has a length of 0.8 m, a mass of 0.12 kg, and a tension of 135 N. a. What is the mass per unit of length of this string? b. What is the speed of a wave on this string? Suppose that the string in exercise 7 is plucked so that there are two nodes along the string in addition to those at either end. What is the wavelength of the interfering waves for this mode? What is the frequency of a sound wave with a wavelength of 0.85 m traveling in room-temperature air (v = 340 m/s)? A certain pigment absorbs green light, while reflecting blue and red wavelengths. If a surface coated with this pigment is illuminated by white light, what is the color of the light reflected from... Microwaves used in laboratory experiments often have a wavelength of about 1 cm. What is the frequency of these waves? What is the wavelength of the radio waves from a station broadcasting at 600 kilohertz? What is the frequency of green light waves with a wavelength of 520 nm? X rays often have a wavelength of about 10 -10 m. What is the frequency of such waves? The visible spectrum of colors ranges from approximately 380 nm in wavelength at the violet end to 750 nm at the far red end. a. What are the frequencies associated with these two wavelengths? b.... A man with a height of 1.8 m stands 3.0 m in front of a plane mirror viewing his image. How tall is the image, and how far from the man is the image located A positive lens forms a real image of an object placed 8 cm to the left of the lens. The real image is found 16 cm to the right of the lens. What is the focal length of the lens? If sodium (Na), with an atomic weight of 23, combines with oxygen (O), with an atomic weight of 16, to form the compound Na 2 O, what is the ratio of the mass of sodium to oxygen that you would... The crew of a spaceship traveling with a velocity of 0.6c relative to the Earth measures the distance between two cities on earth (in a direction parallel to their motion) as 600 km. What is the... Which electrons are represented by an electron-dot structure? Why does the fluorine atom tend to gain only one electron? Explain why, for these three substances, the solubility in 20C water goes down as the molecules get larger, but the boiling point goes up. Boiling point/ Solubility Substance 65C CH;-0 infinite 117C... The mass of the J/ is m J = 3.097 GeV and its width is = 91 keV. What is its lifetime? If it is produced with p J = 5 GeV in the L reference frame, what is the distance travelled in a lifetime?... Evaluate R (e + e - hadrons) /(e + e - + - ) At and at Vs = 2.5 GeV Vs = 4 GeV. In a zero-gravity environment, can a rocket-propelled spaceship ever attain a speed greater than the relative speed with which the burnt fuel is exhausted? A 110-lb woman puts all of her weight on one heel of her high-heel shoes. The heel has an area of 0.4 m 2 . What is the pressure that her heel exerts on the ground in pounds per square inch (psi)? A member of the U.S. Congress proposed a scheme to produce energy as follows. Water molecules (H 2 O) are to be broken apart to produce hydrogen and oxygen. The hydrogen is then burned (that is,... For electronic devices such as amplifiers, what are some advantages of transistors compared to vacuum tubes? What are some disadvantages? Are there any situations in which vacuum tubes cannot be... The energy required to remove the 3s electron from a sodium atom in its ground state is about 5 eV. Would you expect the energy required to remove an additional electron to be about the same, or... The sun supplies electromagnetic energy to the earth. It appears to have an effective temperature of approximately 5800 K. On a clear summer day in North America, the energy incident on a surface... A refrigerator using R-12 as the working fluid keeps the refrigerated space at 215C in an environment at 30C. You are asked to redesign this refrigerator by replacing R-12 with the ozone-friendly... A light ray in air enters a block of clear plastic as shown in Figure 9.84. Which of the numbered paths represents the correct one for the ray in the plastic? Justify your choice by appealing to the... Explain why the strings that play lower frequency notes on a guitar or violin are generally thicker and less tightly strung than the strings playing higher notes. Explain why the optimal ratio of moderator to fuel is so much larger for a graphite-moderated (infinite, homogeneous) reactor than for a water-moderated reactor at the same enrichment. The absorption coefficient for crystalline silicon at 300K for a photon of energy 1.3 eV is roughly 70 cm 1 .Compute the thickness of silicon needed to absorb 75%of incoming photons at this energy Assuming that one half of the energy in solar radiation absorbed at the oceans surface is lost to latent heat flux (evaporation), give an order-of-magnitude estimate of the rate at which water vapor... In contrast to traditional hydropower plants where water is stored behind large dams, run of the river (ROR) hydro-plants use flowing water with little or no water storage (pondage). Investigate and... Investigate the production of helium. How was it formed? Why is it found in natural gas? How much of it is recovered? Discuss conservation of the worlds helium resources. A baryon decays strongly into + and + , but not into 0 0 nor into + + , even if all are energetically possible. (1) What can you tell about its isospin? (2) You should check your conclusion... An electron of rest energy mc 2 = 0.511 MeV moves with respect to the laboratory at speed u = 0.6c. Find (a) , (b) P in units of MeV/c, (c) E, and (d) E k . A burst of + mesons (pions) travels down an evacuated beam tube at Fermilab moving at = 0.92 with respect to the laboratory. (a) Compute for this group of pions. (b) The proper mean lifetime of... Verify by calculation that the result of the Michelson-Morley experiment places an upper limit on Earths speed relative to the ether of about 5 km/s. Consider the flow conditions of Example 6.4 for two situations, one in which the flow is completely laminar, and the second for flow that is tripped to turbulence at the leading edge of the plate.... Consider the rotating disk of Problem 6.16. A diskshaped, stationary plate is placed a short distance away from the rotating disk, forming a gap of width g. The stationary plate and ambient air are... Assume that the train shown in Figure 1-14 is 1.0 km long as measured by the observer at C' and is moving at 150 km/h. What time interval between the arrival of the wave fronts at C' is measured by... The x-ray spectrometer on board a satellite measures the wavelength at the maximum intensity emitted by a particular star to be m = 82.8 nm. Assuming that the star radiates like a blackbody, (a)... Consider the photovoltaic solar panel of Example 3.3. The heat transfer coefficient should no longer be taken to be a specified value. (a) Determine the silicon temperature and the electric power... Cooling of outdoor electronic equipment such as in telecommunications towers is difficult due to seasonal and diurnal variations of the air temperature, and potential fouling of heat exchange... Prove that the photoelectric effect cannot occur with a completely free electron, that is, one not bound to an atom. Show that the maximum kinetic energy E k , called the Compton edge, that a recoiling electron can carry away from a Compton scattering event is given by Ex = 2E hf 1+ mc/2hf 2E + mc When light of wavelength 450 nm is incident on potassium, photoelectrons with stopping potential of 0.52 V are emitted. If the wavelength of the incident light is changed to 300 nm, the stopping... Compute for photons scattered at 120 from (a) Free protons, (b) Free electrons, and (c) N 2 molecules in air. Gamma rays emitted by radioactive nuclei also exhibit measurable Compton scattering. Suppose a 0.511 MeV photon from a positron-electron annihilation scatters at 110 from a free electron. What are... Find the momentum of a photon in eV/c and in kgm/s if the wavelength is (a) 400 nm, (b) 1 = 0.1 nm, (c) 3 cm, and (d) 2 nm. x-ray tubes currently used by dentists often have accelerating voltages of 80 kV. What is the minimum wavelength of the x rays they produce? The longest wavelength of light that will cause emission of electrons from cesium is 653 nm. (a) Compute the work function for cesium. (b) If light of 300 nm (ultraviolet) were to shine on cesium,... Under optimum conditions, the eye will perceive a flash if about 60 photons arrive at the cornea. How much energy is this in joules if the wavelength of the light is 550 nm?
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