All Matches

Solution Library

Expert Answer

Textbooks

Search Textbook questions, tutors and Books

Oops, something went wrong!

Change your search query and then try again

Result Not Found

Books FREE
Tutors
Study Help
Ask a Question

Search
Sign In
Register

study help
physics
thermodynamics

Questions and Answers of Thermodynamics

An aluminum wire 10 m (32.8 ft) long is cooled from 38 to -1°C (100 to 30°F). How much change in length will it experience?
A 0.1 m (3.9 in.) rod of a metal elongates 0.2 mm (0.0079 in.) on heating from 20 to 100°C (68 to 212°F). Determine the value of the linear coefficient of thermal expansion for this material.
Railroad tracks made of 1025 steel are to be laid during the time of year when the temperature averages 10°C (50°F). If a joint space of 4.6 mm (0.180 in.) is allowed between the standard 11.9-m
The ends of a cylindrical rod 6.4 mm (0.25 in.) in diameter and 250 mm (10 in.) long are mounted between rigid supports. The rod is stress free at room temperature [20°C (68°F)]; and upon cooling
(a) What are the units for the thermal shock resistance parameter (TSR)? (b) Rank the following ceramic materials according to their thermal shock resistance: glass-ceramic (Pyroceram), partially
Equation 19.9, for the thermal shock resistance of a material, is valid for relatively low rates of heat transfer. When the rate is high, then, upon cooling of a body, the maximum temperature change
A coil of wire 0.20 m long and having 200 turns carries a current of 10 A.(a) What is the magnitude of the magnetic field strength H?(b) Compute the flux density B if the coil is in a vacuum.(c)
There is associated with each atom in paramagnetic and ferromagnetic materials a net magnetic moment. Explain why ferromagnetic materials can be permanently magnetized whereas paramagnetic ones
Consult another reference in which Hund's rule is outlined, and on its basis explain the net magnetic moments for each of the cations listed in Table 20.4.
Estimate (a) The saturation magnetization (b) The saturation flux density of nickel ferrite [(NiFe2O4)8], which has a unit cell edge length of 0.8337 nm.
The chemical formula for manganese ferrite may be written as (MnFe2O4)8 because there are eight formula units per unit cell. If this material has a saturation magnetization of 5.6 × 105 A/m and a
The formula for yttrium iron garnet (Y3Fe5O12) may be written in the form Y3cFe2aFe3dO12, where the superscripts a, c, and d represent different sites on which the Y3+ and Fe3+ ions are located. The
Briefly explain why the magnitude of the saturation magnetization decreases with increasing temperature for ferromagnetic materials, and why ferromagnetic behavior ceases above the Curie temperature.
Briefly describe the phenomenon of magnetic hysteresis, and why it occurs for ferromagnetic and ferrimagnetic materials.
A coil of wire 0.1 m long and having 15 turns carries a current of 1.0 A.(a) Compute the flux density if the coil is within a vacuum.(b) A bar of an iron-silicon alloy, the B-H behavior for which is
A ferromagnetic material has a remanence of 1.25 teslas and a coercivity of 50,000 A/m. Saturation is achieved at a magnetic field intensity of 100,000 A/m, at which the flux density is 1.50 teslas.
The following data are for a transformer steel:(a) Construct a graph of B versus H.(b) What are the values of the initial permeability and initial relative permeability?(c) What is the value of the
Demonstrate that the relative permeability and the magnetic susceptibility are related according to Equation 20.7.
An iron bar magnet having a coercivity of 4000 A/m is to be demagnetized. If the bar is inserted within a cylindrical wire coil 0.15 m long and having 100 turns, what electric current is required to
A bar of an iron-silicon alloy having the B-H behavior shown in Figure 20.29 is inserted within a coil of wire 0.20 m long and having 60 turns, through which passes a current of 0.1 A.(a) What is the
Estimate saturation values of H for single-crystal iron in [100], [110], and [111] directions.
The energy (per unit volume) required to magnetize a ferromagnetic material to saturation (Es) is defined by the following equation:That is, Es is equal to the product of Î¼0 and the
Cite the differences between hard and soft magnetic materials in terms of both hysteresis behavior and typical applications.
Assume that the commercial iron (99.95 wt% Fe) in Table 20.5 just reaches the point of saturation when inserted within the coil in Problem 20.1. Compute the saturation magnetization.
Figure 20.30 shows the B-versus-H curve for a steel alloy.(a) What is the saturation flux density?(b) What is the saturation magnetization?(c) What is the remanence?(d) What is the coercivity?(e) On
Briefly explain the manner in which information is stored magnetically.
For a superconducting material at a temperature T below the critical temperature TC, the critical field HC (T), depends on temperature according to the relationshipwhere HC(0) is the critical field
Using Equation 20.14, determine which of the superconducting elements in Table 20.7 are superconducting at 3 K and in a magnetic field of 15,000 A/m.
It is possible to express the magnetic susceptibility χm in several different units. For the discussion of this chapter, χm was used to designate the volume susceptibility in SI units, that is, the
Cite the differences between type I and type II superconductors.
Briefly describe the Meissner effect.
(a) Explain the two sources of magnetic moments for electrons. (b) Do all electrons have a net magnetic moment? Why or why not?
The magnetic flux density within a bar of some material is 0.435 tesla at an H field of 3.44 × 105 A/m. Compute the following for this material: (a) The magnetic permeability. (b) The magnetic
The magnetization within a bar of some metal alloy is 3.2 × 105 A/m at an H field of 50 A/m. Compute the following: (a) The magnetic susceptibility. (b) The permeability. (c) The magnetic flux
Compute (a) The saturation magnetization. (b) The saturation flux density for cobalt, which has a net magnetic moment per atom of 1.72 Bohr magnetons and a density of 8.90 g/cm3.
Confirm that there are 2.2 Bohr magnetons associated with each iron atom, given that the saturation magnetization is 1.70 × 106 A/m, that iron has a BCC crystal structure, and that the unit cell
Assume there exists some hypothetical metal that exhibits ferromagnetic behavior and that has (1) a simple cubic crystal structure (Figure 3.24), (2) an atomic radius of 0.153 nm, and (3) a
A cobalt-nickel alloy is desired that has a saturation magnetization of 1.3 × 106 A/m. Specify its composition in weight percent nickel. Cobalt has an HCP crystal structure with c/a ratio of 1.623,
Design a cubic mixed-ferrite magnetic material that has a saturation magnetization of 4.6 × 105 A/m.
Visible light having a wavelength of 6 × 10-7 m appears orange. Compute the frequency and energy of a photon of this light.
It is desired that the reflectivity of light at normal incidence to the surface of a transparent medium be less than 6.0%. Which of the following materials in Table 21.1 are likely candidates: silica
Briefly explain how reflection losses of transparent materials are minimized by thin surface coatings.
The index of refraction of corundum (Al2O3) is anisotropic. Suppose that visible light is passing from one grain to another of different crystallographic orientation and at normal incidence to the
Zinc telluride has a band gap of 2.26 eV. Over what range of wavelengths of visible light is it transparent?
Briefly explain why the magnitude of the absorption coefficient (β in Equation 21.18) depends on the radiation wavelength.
The fraction of non reflected radiation that is transmitted through a 10-mm thickness of a transparent material is 0.90. If the thickness is increased to 20 mm, what fraction of light will be
Derive Equation 21.19, starting from other expressions given in the chapter.
The transmissivity T of a transparent material 20 mm thick to normally incident light is 0.85. If the index of refraction of this material is 1.6, compute the thickness of material that will yield a
Briefly explain what determines the characteristic color of (a) A metal and (b) A transparent nonmetal.
Distinguish between materials that are opaque, translucent, and transparent in terms of their appearance and light transmittance.
Briefly explain why some transparent materials appear colored while others are colorless.
Briefly explain why amorphous polymers are transparent, while predominantly crystalline polymers appear opaque or, at best, translucent.
(a) In your own words describe briefly the phenomenon of luminescence. (b) What is the distinction between fluorescence and phosphorescence?
Briefly explain the operation of a photographic light meter.
Compute the difference in energy between metastable and ground electron states for the ruby laser.
At the end of Section 21.14 it was noted that the intensity of light absorbed while passing through a 16-kilometer length of optical fiber glass is equivalent to the light intensity absorbed through
(a) Briefly describe the phenomenon of electronic polarization by electromagnetic radiation. (b) What are two consequences of electronic polarization in transparent materials?
Briefly explain why metals are opaque to electromagnetic radiation having photon energies within the visible region of the spectrum.
Can a material have an index of refraction less than unity? Why or why not?
Compute the velocity of light in calcium fluoride (CaF2), which has a dielectric constant ∈r of 2.056 (at frequencies within the visible range) and a magnetic susceptibility of -1.43 × 10-5.
The indices of refraction of fused silica and a soda-lime glass within the visible spectrum are 1.458 and 1.51, respectively. For each of these materials determine the fraction of the relative
Using the data in Table 21.1, estimate the dielectric constants for borosilicate glass, periclase (MgO), poly(methyl methacrylate), and polypropylene, and compare these values with those cited in the
Gallium arsenide (GaAs) and gallium phosphide (GaP) are compound semiconductors that have room-temperature band gap energies of 1.42 and 2.25 eV, respectively, and form solid solutions in all
Ten kg of a liquid occupies 8000 cm3. Its density, specific volume, and specific gravity are (p, v, SG): (A) (1250 kg/m3, 0.0008 m3/kg, 1.25) (B) (0.0008 kg/m3, 1250 m3/kg, 0.8) (C) (1250 kg/m3,
A force of 100 N acts on the 10-kg mass of Fig. 1.16. The mass accelerates at:(A) 10 m/s2(B) 1 m/s2(C) 0.1 m/s2(D) Can't tellFigure 1.16
An atmospheric pressure on a mountain is measured as 420 mm of mercury. Using SGHG = 13.6, the pressure in SI units is nearest: (A) 56 kPa (B) 62 kPa (C) 68 kPa (D) 72 kPa
A spring with spring constant 400 N/m is attached to a 40-kg-frictionless piston and is stretched a distance of 20 cm, as shown in Fig. 1.17. The pressure in the cylinder is nearest:(A) 30 kPa
As we take a shower, the water feels cooler than when we first entered the shower, so we turn up the temperature. Why is that? (A) It takes time for the water to heat up due to the pipes. (B) Our
A 2000-kg vehicle is to be crashed into a rigid barrier supported by a very stiff spring (see Fig. 1.18) that simulates a crash into a smaller 1400-kg vehicle. What should be the spring constant K if
In thermodynamics, we really are not interested in how energy is used. True or false? Comment.
Select the energy source that is not sustainable. i) Hydropower from dams ii) Energy from wind turbines iii) Electricity from solar photovoltaic panels iv) Power plants powered by wood v) Power
Select a major responsibility of mechanical engineers in the mid-1800s: i) To design power plants ii) To oversee the operation of trains iii) To design mining equipment used to mine coal iv) To
Identify if a system or a control volume should be selected for each of the following:i) A shock absorber (see Fig. 1.19)ii) The turbine in a damiii) Heating the water in a pressure cooker from cool
A balloon, the control volume, is pressurized with air, the system, and held fixed immediately after the air is let free to go. Sketch the system and the control volume at t = 0 and a moment (more
How large would a sphere have to be at sea level to hold one trillion molecules of air at standard conditions?
Is ketchup, or catsup, a fluid or a solid? What is it? Check with Mr. Google.
What is the advantage of using slugs as the unit of mass in the English system?
The specific volume of ice at 32° F is 0.01747 ft3 /lbm. What is its density? Will it float? If it didn't float, what would be the consequences?
Calculate the specific gravity of mercury if pHG = 13 600 kg/m3. How much would 2 m3 of mercury weigh?
Determine the entries in the following table if g = 9.81 m/s2 and V = 2 m3. v (m3 /kg) r (kg/m3) m (kg) W (N) a) 5 b) 2 c) 1000 d) 1000
Determine the entries in the following table if g = 32.2 ft/s2 and V = 20 ft3. v (ft3 /lbm) p (lbm/ft3) m(lbm) W(lbf) a) 50 b) 0.2 c) 1000 d) 500
A substance occupies 8 m3 and has a specific volume of 4 m3 /kg. Determine its density, specific gravity, mass, and weight.
A substance, with a density of 0.2 lbm/ft3, occupies 20 ft3. Calculate its specific volume, specific gravity, mass, and weight.
Which of the following would utilize a control volume rather than a system? (A) The gas in a cylinder during compression (B) The gas in a cylinder during exhaust (C) The melting of ice cubes in a
Select the process from the following that can be considered a quasi-equilibrium process: i) A baseboard heater in a room of a house ii) The compression of air by the piston in the cylinder of a
Calculate the specific gravity of air at i) Standard conditions, ii) 5000-m altitude, iii) 10 000-m altitude. Refer to Table B-1.
If a tire gage reads 2.1 kg/cm2 (a former European measure), determine the absolute pressure in the tire in kPa at i) Sea level, ii) 1000-m elevation, iii) 5000-m elevation. Refer to Table B-1.
A tire gage measures a pressure of 3.4 kg/cm2 (a former European measure). If a differential manometer using mercury were used to measure this pressure, what would its reading be in millimeters?
A differential water manometer (see Fig. 1.8) shows a Δh of 25 cm. Air is above the water on both sides. What is the difference in pressure between the two sides in kPa gage? In inches of Hg?
A mercury differential manometer (see Fig. 1.8) has a Δh of a) 10 cm b) 28 cm. If air is above the mercury on both sides, what is the difference in pressure in kPa?
The pressure in a container on a mountain at an elevation of 25,000 ft is measured to be a) 5 psi b) 20 psi. What is the absolute pressure in psia? In psfa?
A thermistor has a resistance of 3000Ω at 25ºC. If β = 4220 K, determine its resistance at a) 60ºC, b) 120ºC, c) 180ºC.
The mercury thermometer of Fig. 1.22 has a 6-mm-diameter rigid sphere that holds the mercury. If the temperature increases bya) 20ºC,b) 40ºC,c) 60ºC, estimate the height the mercury
An automobile with a mass of 2500 lbm is traveling at 60 mph. What is the kinetic energy of the car?
A good approximation to gravity above the surface of the Earth is g = 9.81 - 3.32 Ã— 10-6h m/s2, where h is the distance above the Earth's surface in meters. The commercial airplane in
Which of the following cannot be modeled as a quasi-equilibrium process? (A) The air escaping from a pressurized balloon being let free (B) The expansion of the air in a piston operating at 4000
Superheated steam exists at 6.5 MPa and 675° C. The enthalpy is nearest: (A) 3828 kJ/kg (B) 3832 kJ/kg (C) 3836 kJ/kg (D) 3840 kJ/kg
A 1-m-diameter bike tire is pumped up to 500 kPa. It is assumed to have a circular cross section with a diameter of 2 cm. The mass of 20° C air in the tire is nearest: (A) 0.0059 kg (B) 0.0082
The cylinder shown in Fig. 2.28 contains 0.02 kg of air. The weight of the frictionless piston is nearest:(A) 8000 N(B) 6000 N(C) 4000 N(D) 3000 NFigure 2.28
The mass of air contained in a rigid 20-L volume at 3 MPa with a temperature of 130 K is nearest: (A) 2.7 kg (B) 2.1 kg (C) 1.8 kg (D) 1.5 kg

Showing 6300 - 6400 of 7587

First
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
Last

Get In Touch

About Us
Contact Us
Career
Jobs
FAQ
Campus Ambassador

Company Info

Security
Copyrights
Privacy Policy
Terms & Condition
SolutionInn Fee
Scholarship

Services

Sitemap
Fun
Definitions
Become Tutor
Study Help Categories
Recent Questions
Expert Questions

Copyright © 2024 SolutionInn All Rights Reserved.

Get the SolutionInn - Study Help App