What is the energy of the photon that, when absorbed by a hydrogen atom, could cause the following?
(a) an electronic transition from the n = 3 state to the n = 6 state
(b) an electronic transition from the n = 3 state to the n = 8 state
In: Physics
What are ways in which businesses pose a threat to the environment? In dealing with environmental harm, what should be the guiding principle for businesses?
In: Physics
A 1.00Kg horseshoe at 900°C is put in a 4.00Kg bath of water at 10°C. assuming that no energy is lost by heat to the surroundings, determine the total entropy change of the wather + horesehoe system. (HINT think about dQ_r)
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1 of 20
Which of the following is the most accurate statement concerning charge?
| a | Charge is one of the seven fundamental dimensions found in nature. |
| b | Charge is a derived dimension (current • time), with SI units of Coulombs. |
| c | Charge is a derived dimension (current • time), with SI units of amperes. |
| d | Charge is a fundamental quantity found in all elementary particles such as protons, electrons, and neutrons. |
| e | The electrical force between two charges is directly proportional to the distance between the two charges. |
Question
2 of 20
Which of the following is the most accurate statement concerning electrical force?
| a | Electrical force is a derived dimension, with SI units of Newton/meter. |
| b | In most cases, the electrical force between two particles is roughly equivalent to the gravitational force between the particles, but opposite in direction. |
| c | Electrical force is one of the seven fundamental dimensions, with SI units of Newton. |
| d | Electrical force obeys the inverse square law. |
| e | Like the gravitational force, the electrical force is always attractive, never repulsive. |
Question
3 of 20
Which of the following is the most accurate statement concerning the first law of thermodynamics?
| a | The first law of thermodynamics describes the relationship between systems in thermal equilibrium. |
| b | The first law of thermodynamics describes the relationship between heat, work, and internal energy in a thermodynamic system. |
| c | The first law of thermodynamics describes the conservation of energy in an open thermodynamic system. |
| d | The first law of thermodynamics describes the conservation of energy in a closed thermodynamic system. |
| e | More than one of given statements are accurate. |
Question
4 of 20
What is the most accurate statement concerning the second law of thermodynamics?
| a | The Carnot cycle involves an isothermal expansion followed by an isobaric compression. The efficiency of this partial cycle is normally about 96%. |
| b | The second law of thermodynamics requires heat to flow spontaneously from a cooler object to a warmer object. This is the basis for a refrigerator. |
| c | A closed thermodynamic system absorbs heat at a high temperature and then converts the heat absorbed into useful work at a lower temperature. |
| d | An isothermal process requires the temperature and pressure in a closed thermodynamic system to remain constant. |
| e | No cyclic thermodynamic process can convert heat completely into mechanical work. |
Question
5 of 20
What is the most accurate statement concerning the relationship between entropy and the second law of thermodynamics?
| a | Entropy provides a quantitative measure of the disorder of a system. |
| b | Entropy is equal to the ratio of the heat added to a system and the absolute temperature of the system. |
| c | Like energy, entropy is required to be conserved in both reversible and irreversible thermodynamic processes. |
| d | More than one of these statements (a, b or c) are accurate. |
| e | None of the statements (a, b or c) is accurate. |
Question
6 of 20
If you run a Carnot heat engine in reverse, which of the following statements must be true?
| a | Heat enters the gas at the cold reservoir and goes out of the gas at the hot reservoir. |
| b | The amount of heat transferred at the hot reservoir is equal to the amount of heat transferred at the cold reservoir. |
| c | The engine is able to perform a net amount of useful work, such as pumping water from a well, during each cycle. |
| d | The engine can transfer heat from a cold object to a hot object. |
| e | More than one of the above statements are true. |
Question
7 of 20
What is the most accurate statement concerning Gauss's law?
| a | Gauss's law provides a quantitative relationship between the electric field established and the quantity of charge present when two point charges form a dipole. |
| b | Gauss's law provides a quantitative relationship between the scalar nature of electric force and the vector nature of electric flux. |
| c | Gauss's law provides a quantitative relationship between electric charge and the electric field associated with the electric charges enclosed on the surface of a three-dimensional object like a sphere. |
| d | Gauss's law uses superposition to estimate the scalar difference between lines of electric flux entering or leaving a closed two-dimensional surface. |
| e | More than one of the statements (a, b, c or d) are accurate. |
Question
8 of 20
If the electric field is "E" at a distance "d" from a point charge, its magnitude will be 2E at a distance______
| a | d/4. |
| b | d/2. |
| c | d/?2. |
| d | d ? 2. |
| e | 2d. |
Question
9 of 20
Two protons close to each other are released from rest and are completely free to move. After being released, which statement(s) is/are accurate?
| a | Their speeds gradually decrease to zero as they move apart. |
| b | Their speeds gradually increase as they move apart. |
| c | Their accelerations gradually increase as they move apart. |
| d | Their accelerations gradually decrease to zero as they move apart. |
| e | More than one of the statements (a, b, c or d) are accurate. |
In: Physics
1) Suppose one force vector is 100 N at theta= 45 degrees, and a second force vector is 75 N at theta =123 degrees both with respect to the positive x-axis. What is a third force that would cause zero net force if all forces are acting on the same mass particle?
2) Suppose one force vector is 150 N at theta = 45 degrees, and
a second force vector is 172 N at theta =
300 degrees both with respect to the positive x-axis. What is a
third force that would cause zero net force if all forces are
acting on the same mass particle?
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3) Consider a very (infinitesimally!) thin but massive rod, length L (total mass M), centered around the origin, sitting along the x-axis. (So the left end is at (-L/2, 0,0) and the right end is at (+L/2,0,0) Assume the mass density λ (which has units of kg/m) is not uniform, but instead varies linearly with distance from the origin, λ(x) = c|x|.
d. In the limit of large z what do you expect for the functional form for gravitational potential? (Hint: Don’t just say it goes to zero! It’s a rod of mass M, when you’re far away what does it look like? How does it go to zero?) What does “large z” mean here? Use the binomial (or Taylor) expansion to verify that your formula does indeed give exactly what you expect. (Hint: you cannot Taylor expand in something BIG, you have to Taylor expand in something small.)
e. Can you use Gauss’ law to figure out the gravitational potential at the point (0, 0, z)? (If so, do it and check your previous answers. If not, why not?)
In: Physics
Calculate the Coulomb barrier height (in terms of MeV) for two
nuclei, each with mass number 9 and atomic number 4, when they are
just touching.
In: Physics
A. Guillaume puts a bottle of soft drink in a refrigerator and leaves it there until its temperature has dropped 15.7 K .
What is the magnitude of its temperature change |ΔT|= 15.7 K in degrees Celsius?
B. A glass flask whose volume is 1000 cm3 at a temperature of 0.300 ∘C is completely filled with mercury at the same temperature. When the flask and mercury are warmed together to a temperature of 52.0 ∘C , a volume of 8.25 cm3 of mercury overflows the flask.
If the coefficient of volume expansion of mercury is βHg = 1.80×10−4 /K , compute βglass, the coefficient of volume expansion of the glass.
Express your answer in inverse kelvins.
C. Consider an ideal gas at 27.0 degrees Celsius and 1.00 atmosphere pressure. Imagine the molecules to be uniformly spaced, with each molecule at the center of a small cube.
What is the length L of an edge of each small cube if adjacent cubes touch but don't overlap?
Express your answer numerically in meters.
D. Determine the temperature at which the Celsius and Fahrenheit scales give the same numerical reading (TC=TF).
E. A glass is filled to the brim with 360.0 mL of water at 100.0 ∘C.
If the temperature of glass and water is decreased to 20.0 ∘C, how much water could be added to the glass?
F. A storage tank at STP contains 26.9 kg of nitrogen (N2). What is the volume of the tank? What is the pressure if an additional 25.3 kg of nitrogen is added without changing the temperature?
G. 60.5 L of oxygen at 16.0 ∘C and an absolute pressure of 3.25 atm are compressed to 38.6 Land at the same time the temperature is raised to 51.0 ∘C. What will the new pressure be?
H.
What is the rms speed of nitrogen molecules contained in a 7.9 m3 volume at 2.9 atm if the total amount of nitrogen is 2300 mol ?
Express your answer to two significant figures and include the appropriate units.
In: Physics
Possible Duplicate:
From how high could have Felix Baumgartner jumped without
disintegrating like a shooting star?
If a human can skydive from an altitude of 24 miles (39 km), and a satellite can stay in geostationary orbit at 22,236 miles (35,786 km), then what is the maximum altitude from which a human can theoretically "skydive."
Furthermore, what would be that humans' fastest speed? (Felix went 834 mph.)
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A. A convex lens has a focal length of 5.74704 cm. The object
distance is 7.11538 cm. Find the image distance.
Answer in units of cm. Find the magnification.
B. A concave lens has a focal length of 35.0689 cm. The object
distance is 17.2727 cm. Find the image distance.
Answer in units of cm. Find the
magnification.
C. A convex lens has a focal length of 10.4082 cm. The object
distance is 6.07143 cm. Find the image distance.
Answer in units of cm.
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1. FM radio stations use radio waves with frequencies from 88.0 to 108 MHz to broadcast their signals. Assuming that the inductance in Figure 24.4 has a value of 7.00 × 10-7 H, determine the range of capacitance values that are needed so the antenna can pick up all the radio waves broadcasted by FM stations.
2. An ac series circuit has an impedance of 114 Ω , and the phase angle between the current and the voltage of the generator is φ = -77 ˚. The circuit contains a resistor and either a capacitor or an inductor. Find (a) the resistance R and (b) the capacitive reactance XC or the inductive reactance XL, whichever is appropriate.
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Two thin lenses with a focal length of magnitude 12.0 cm, the first diverging and the second converging, are located 9.00 cm apart. An object 2.50 mm tall is placed 20.0 cm to the left of the first (diverging) lens. (a) How far from this first lens is the final image formed? (b) Is the final image real or virtual? (c) What is the height of the final image? Is it noninverted or inverted?
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A crate of mass 9.0 kg is pulled up a rough incline with an initial speed of 1.52 m/s. The pulling force is 90 N parallel to the incline, which makes an angle of 20.8
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You throw a penny (m = 2.5 g) with an initial speed of 9.4 m/s at 25◦ above the horizontal. At the maximum height of your thrown penny’s path another penny, traveling straight upward, collides and bounces off of your penny. The speed of the second penny at the moment of collision was 4.1 m/s. a) Determine the maximum height your thrown penny reaches as a result of this collision. b) How far, horizontally, does your penny travel before reaching the ground (assume that the penny was thrown from the ground). Hint: Make sure to account for BOTH directions at ALL times.)
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A ballplayer catches a ball 3.2 s after throwing it vertically upward. With what speed did he throw it? What height did it reach?
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