Numerade

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Aparna Shakti

Numerade educator

ssm An X-ray tube contains a silver (Z = 47) target. The high voltage in this tube is increased from zero. Using the Bohr model, find the value of the voltage at which the $K_{\alpha}$ X-ray just appears in the X-ray spectrum.

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Umar Sohail Qureshi

Numerade educator

The drawing shows a ray of light traveling through three materials whose surfaces are parallel to each other. The refracted rays (but not the reflected rays) are shown as the light passes through each material. A ray of light strikes the $a-b$ interface at a $50.0^{\circ}$ angle of incidence. The index of refraction of material $a$ is $n_{a}=1.20$ The angles of refraction in materials $b$ and $c$ are, respectively, $45.0^{\circ}$ and $56.7^{\circ} .$ Find the indices of refraction in these two media.

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David Collins

Numerade educator

Hydrazine, ammonia, and hydrogen azide all contain only nitrogen and hydrogen. The mass of hydrogen that combines with $1.00 \mathrm{g}$ of nitrogen for each compound is $1.44 \times 10^{-1} \mathrm{g}$ $2.16 \times 10^{-1} \mathrm{g},$ and $2.40 \times 10^{-2} \mathrm{g},$ respectively. Show how these data illustrate the law of multiple proportions.

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INSTANT ANSWER

Explain how the two telephone call graphs for calls made during the month of January and calls made during the month of February can be used to determine the new telephone numbers of people who have changed their telephone numbers.

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Oswaldo Jiménez

Numerade educator

In order to estimate the height of a building, two students stand at a certain distance from the building at street level. From this point, they find the angle of elevation from the street to the top of the building to be 35°. They then move 250 feet closer to the building and find the angle of elevation to be 53°. Assuming that the street is level, estimate the height of the building to the nearest foot.

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INSTANT ANSWER

Sulfur exhibits two solid phases, rhombic and monoclinic. Use the accompanying phase diagram for sulfur to answer the following questions. (The phase diagram is not to scale.) a. How many triple points are in the phase diagram? b. What phases are in equilibrium at each of the triple points? c. What is the stable phase at 1 atm and $100 .^{\circ} \mathrm{C}$ ? d. What are the normal melting point and the normal boiling point of sulfur? e. Which is the densest phase? f. At a pressure of $1.0 \times 10^{-5}$ atm, can rhombic sulfur sublime? g. What phase changes occur when the pressure on a sample of sulfur at $100 .^{\circ} \mathrm{C}$ is increased from $1.0 \times 10^{-8}$ atm to 1500 atm?

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Hubert Agamasu

Numerade educator

Three ropes pull on a knot shown in Figure P3.6a. The knot is not accelerating. A partially completed force diagram for the knot is shown in Figure P 3.6 $\mathrm{b}$ . Use qualitative reasoning (no math) to determine the magnitudes of the forces that ropes 2 and 3 exert on the knot. Explain in words how you arrived at your answers.

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INSTANT ANSWER

A case study in the chapter analyzed purchasing power parity for several countries using the price of Big Macs. Here are data for a few more countries: a. For each country, compute the predicted exchange rate of the local currency per U.S. dollar. (Recall that the U.S. price of a Big Mac was \$4.93.) b. According to purchasing-power parity, what is the predicted exchange rate between the Hungarian forint and the Canadian dollar? What is the actual exchange rate? c. How well does the theory of purchasing-power parity explain exchange rates?

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ANSWERED

Christopher Dzorkpata

Numerade educator

A 1100 -kg car pulls a boat on a trailer. (a) What total force resists the motion of the car, boat, and trailer, if the car exerts a 1900 -N force on the road and produces an acceleration of 0.550 $\mathrm{m} / \mathrm{s}^{2} ?$ The mass of the boat plus trailer is 700 $\mathrm{kg}$ . (b) 80\% of the force in the hitch between the car and the trailer if trailer?

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Umar Sohail Qureshi

Numerade educator

(II) The position of a rabbit along a straight tunnel as a function of time is plotted in Fig. $36 .$ What is its instanta- neous velocity $(a)$ at $t=10.0 \mathrm{s}$ and $(b)$ at $t=30.0 \mathrm{s}$ ? What is its average velocity $(c)$ between $t=0$ and $t=5.0 \mathrm{s}, \quad(d)$ between $t=25.0 \mathrm{s}$ and $t=30.0 \mathrm{s},$ and $(e)$ between $t=40.0 \mathrm{s}$ and $t=50.0 \mathrm{s} ?$

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Amanda W.