The steps in the heating of a metal seat in a park are:
Step 1: Heat travels from the sun to Earth
Step 2: Heat travels through atmosphere to the top of the seat
Step 3: Heat from the top of the seat travels through the seat to the lower parts of the seat.
-- Heat is transferred by radiation in Step 1 and Step 2. <em>(B)</em>
-- From the top of the seat to the bottom, heat is transferred by conduction.
There's no convection happening anywhere in the park-hot-seat scenario.
Answer:
Belgium
France
Luxembourg
Explanation:
These are the ones that are in the High Productivity chart, but not in the HDI chart
The question is missing alternatives. Here is the complete question.
An infrared spectrometer on Dawn found something unexpected on Ceres's surface. Its presence suggested that Ceres might have formed farther from the Sun, or been impacted by objects from a more-distant part of the solar system. What was this finding?
1. The fact that Ceres is covered with small dark particles that appear identical to the composition of Uranus's rings.
2. The presence of a thick cloud layer made of sulfuric acid, similar to what is observed at Venus.
3. The presence of clay-like minerals with ammonia bound up in them.
4. The infrared spectrum of Ceres's surface is essentially identical to that of most objects in the Kuiper Belt.
Answer: 3. The presence of clay-like minerals with ammonia bound up in them.
Explanation: The discovery of ammonia clay-like minerals in Ceres is surprising because it would be encoutered in planets that are far from the Sun, since ammonia requires colder temperatures, which is found beyond Jupiter's orbit, to condense. This finding can ascertain not only the origins of the dwarf planet as how the solar system was formed, were organized and evolved, because understanding where smaller planets are formed is important to determine their destiny.
A) We want to find the work function of the potassium. Apply this equation:
E = 1243/λ - Φ
E = energy of photoelectron, λ = incoming light wavelength, Φ = potassium work function
Given values:
E = 2.93eV, λ = 240nm
Plug in and solve for Φ:
2.93 = 1243/240 - Φ
Φ = 2.25eV
B) We want to find the threshold wavelength, i.e. find the wavelength such that the energy E of the photoelectrons is 0eV. Plug in E = 0eV and Φ = 2.25eV and solve for the threshold wavelength λ:
E = 1243/λ - Φ
0 = 1243/λ - Φ
0 = 1243/λ - 2.25
λ = 552nm
C) We want to find the frequency associated with the threshold wavelength. Apply this equation:
c = fλ
c = speed of light in a vacuum, f = frequency, λ = wavelength
Given values:
c = 3×10⁸m/s, λ = 5.52×10⁻⁷m
Plug in and solve for f:
3×10⁸ = f(5.52×10⁻⁷)
f = 5.43×10¹⁴Hz
