Which of the following best describes a filtergram?
A) It is a region inside a star where energy is carried outward as rising hot gas.
B) It is composed of ionized gas trapped in a magnetic arch rising up through the photosphere.
C) It is an atom in which an electron has moved from a lower to a higher energy level.
D) It is a photograph taken in the light of a specific region of the spectrum of the Sun.
D
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When it was determined that Sedna has a perihelion distance that is three times further out than Pluto and such an eccentric orbit that it has a period of thousands of years, it was placed in the:
A) Trojan Asteroids. B) Kuiper Belt. C) Kirkwood Gap. D) Oort Cloud. E) Rogue Comets.
Herschel's original disk model placed us close to the center of the Galaxy
Indicate whether the statement is true or false
The audible range of sound is from 20 Hz to ______________ kHz
Fill in the blank(s) with correct word
A very thin silicon chip is bonded to a 6-mm thick aluminum substrate by a 0.02-mm thick epoxy glue. Both surfaces of this chip-aluminum system are cooled by air at 250C, where the convective heat transfer coefficient of air flow is 100 W/(m2 K). If the heat dissipation per unit area from the chip is 104 W/m2 under steady state condition, draw the thermal circuit for the system and determine the operating temperature of the chip.
GIVEN
Silicon chip bonded to 6-mm thick aluminum substrate bye 0.02-mm thick epoxy glue
Air temperature(T?)=250C
Convective heat transfer coefficient(h?)=100 W/(m2 K)
Heat dissipation from chip(q/A)= 104 W/m2
FIND
Draw thermal circuit of system
Operating temperature of the chip.
ASSUMPTIONS
1-Dimensional Steady state conditions prevail
Negligible heat loss from the sides
Isothermal chip
Negliglble radiation
SKETCH
