GGR370H5 Lecture Notes - Lecture 9: Urban Structure, Gateway Cities, Urban Sprawl

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28 Nov 2020

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The transition from a rural to an urban society. Statistically , urbanization reflects an increasing proportion of the population living in settlements defined as urban , primarily through net rural to urban migration . The level of urbanization is the percentage of the total population living in towns and cities while the rate of urbanization is the rate at which it grows. Global urbanization demographic trends: natural increase more births than deaths. Associated with the period of time where a city is urbanizing. " 40 - 60"t. of urban growth in the developing world: international migrations. " migration to major gateways spill- over to nearby cities. Trickle - down effect people might migrate to cities that are close to such gateway cities urbanization is often associated with new forms of employment, economic activity and lifestyle choices urban form. Refers to the spatial imprint of an urban transport system as well as the adjacent physical infrastructures .

Related Questions

Monochromatic light of wavelength λ diffracts through a narrow slit S in an otherwise opaque screen. On the other side of the slit, there is a plane mirror perpendicular to the screen, with a distance h from the slit. A lens is placed at the far end of the mirror, and a viewing screen A is placed at the focal distance of the lens. Light from the slit that travels directly through the lens to A interferes with light from the slit that reflects from the mirror, through the lens to A. This arrangement is known as Lloyd's Mirror, and it produces a double-slit interference pattern from a single slit.

Are there any phase changes due to reflection?

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The emergence of line spectra from a gas when a current passesthrough it was an observed phenomenon waiting for an explanation inthe early 20th century. The atomic line spectra coming fromelements such as hydrogen had been analyzed since the late 19thcentury. By studying the wavelength of the emerging radiation ofhydrogen, experimenters found (often by trial and error) that thewavelengths in those spectra were described by the formula

\frac{1}{\lambda} = R \left( \frac{1}{n_1^2} - \frac{1}{n_2^2}\right),
where R is known as the Rydberg constant. It has a value of R =1.097 \times 10^{7}\; \rm m^{-1}. The variables n_1 and n_2 areinteger numbers (n_1 = 1,2,3,4,\dots). As experiments continued,scientists began to see more and more characteristic lines emergingfrom the hydrogen spectrum. Each of them corresponded to awavelength predicted by this formula with some integer values forn_1 and n_2.

In 1913, Niels Bohr provided an explanation for the observationsmade in experiments by proposing that each electron in an atom hadonly certain allowable energy levels. Furthermore, he postulatedthat when an electron changed its energy level, it must emit orabsorb a single photon with the energy equal to the energydifference between the two levels.

With this interpretation, the variables n_1 and n_2 acquired newsignificance. Bohr's model predicted that n_2 was the initialenergy state of the atom (n_initial) and that n_1 was the finalstate of the atom (n_final). A photon with the predicted wavelengthwas created when an atom made a transition from its initial energystate to a lower final energy state. The equation now read

\frac{1}{\lambda} = R \left( \frac{1}{n_{\rm final}^2} -\frac{1}{n_{\rm initial}^2} \right).
Bohr's model also predicted that a photon of the appropriatewavelength (given by the same formula) could promote an atom from alower energy level to a higher one.

In this problem, we explore the photon characteristics necessaryfor transitions between energy levels in hydrogen and singlyionized {\rm He}^+, whose energy levels are accurately predicted bythe Bohr model.
What is the change in energy DeltaE of the hydrogen atom as theelectron makes the transition from the n=3 energy level to the n=1energy level?
Express your answer numerically in electron volts.

b. When an atom makes a transition from a higher energy level to alower one, a photon is released. What is the wavelength of thephoton that is emitted from the atom during the transition from n=3to n=1?
Express your answer numerically in angstroms.

c.

When the hydrogen atom makes the transition from the n=2 to the n=1energy level, it emits a photon. This photon can be absorbed by toa singly ionized helium atom ({\rm He}^+) in its second energylevel (n_{\rm initial} = 2), causing it to move to a higher energylevel. To what final energy level number n_final can the photonpromote the helium ion?

Note that {\rm He}^+ has two protons in its nucleus and a singleelectron.
Express your answer as an integer.

Please answer fully, Thank you
a.

In your work for an optical research company, you are asked to consider the triangular shaped prism shown in Figure P34.48. Light enters the left slanted side of the prism from air at normal incidence, reflects from the top surface by total internal reflection, and then refracts out of the right slanted surface.

(a) Your supervisor asks you to determine the range of angles over which visible light exits the right slanted surface due to dispersion in the material.

(b) An actual physical prism of the shape in Figure P34.48 is then made from cubic zirconia with and , and it doesn't work as planned. Explain to your supervisor why not.

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GGR370H5 Lecture Notes - Lecture 9: Urban Structure, Gateway Cities, Urban Sprawl

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