What forms of electromagnetic radiation from the Sun's emissions do we experience here on Earth? Illustrate how we know this to be the case with one practical example for each form
What will be an ideal response?
Visible light:
We can see light and color, and color is reflected in our eyes.
Earth is not in blackness.
Ultraviolet light:
We need to wear sunscreen.
Humans have evolved with different skin pigments.
Infrared:
We feel heat.
Earth isn't a frozen rock
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The increase in specimen strength with plastic strain is _____________ hardening.
Fill in the blank(s) with the appropriate word(s).
Compared with the photons of light that shines on glass, the emerging photons are
A) the same photons. B) different though identical. C) a mixture of being the same and different.
Design (i.e., determine the overall area and a suitable arrangement of shell and tube passes) a tubular-feed water heater capable of heating 2,300 kg/h of water from 210C to 90°C. The following specification are given (a) saturated steam at 920 kPa absolute pressure is condensing on the outer tube surface, (b) heat transfer coefficient on steam side is 6800 W/(m2 K), (c) tubes are of copper, 2.5 cm, 2.3-cm-ID, 24 m long, and (d) water velocity is 0.8 m/s.
GIVEN
• A tubular-feed water heater, condensing saturated steam on outside
• Water flow rate m w= 2300 kg/h = 0.639 kg/s
• Water temperatures Tw,in = 21°C Tw,out = 90°C
• Steam temperature = 920 kPa absolute
• Heat transfer coefficient on steam side h o= 6800 W/(m2 K)
• Tubes are copper Di = 2.3 cm = 0.023 m Do = 2.5 cm = 0.025 m
• Water velocity (V) = 0.8 m/s
FIND
• The transfer area (A) and a suitable arrangement of shell and tube passes
SKETCH
Assuming a single shell pass and two tube passes
PROPERTIES AND CONSTANTS
the thermal conductivity of copper at 127°C (k) = 392 W/(m K)
the saturation temperature of steam at 920 kPa (Ts) = 176°C
for water at the average temperature of 56°C
Density (?) = 984.9 kg/m3
Specific area (cpw) = 4181 J/(kg K)
Thermal conductivity (kw) = 0.653 W/(m K)
Kinematic viscosity (?) = 0.510 × 106 m2/s
Prandtl number (Pr) = 3.23
As the Moon covers the solar disk during a solar eclipse, a flash spectrum of the Sun's chromosphere can be recorded. This flash spectrum reveals an emission spectrum and provides information on the properties of the chromosphere. As the Moon moves from the inner chromosphere to the outer chromosphere, the spectral lines present in the flash spectrum change. What is going on in the chromosphere
that produces the changes in the flash spectrum? I. The temperature of the chromosphere decreases as the distance from the photosphere increases. II. The temperature of the chromosphere increases as the distance from the photosphere increases. III. The density of the chromosphere decreases as the distance from the photosphere increases. IV. The density of the chromosphere increases as the distance from the photosphere increases. a. I & III b. I & IV c. II & III d. II & IV e. I