A, B, and D above.
Star D appears twice as bright as star C
Star C appears twice as bright as star D
Star C appears four times as bright as star D
Star D appears four times as bright as star C
It has a transverse velocity that is toward us.
Its surface temperature is higher than that of the Sun.
It has a radial velocity that is toward us.
It has a radial velocity that is away from us.
It has a transverse velocity that is away from us.
Proportional to temperature
Inversely proportional to temperature
Proportional to temperature to the fourth power
Inversely proportional to temperature to the fourth power
Both a and c above
The Earth's atmosphere easily absorbs it at the upper atmosphere
Very few objects emit at ultraviolet wavelengths
No space-based telescopes operate at ultraviolet wavelengths
Only the lowest mass stars emit ultraviolet light
Poor light gathering power.
Poor resolving power.
Poor magnifying power.
Interference from nearby sources of radio waves.
The low energy of radio photons.
A radio observatory
An adaptive optics observatory
An X-ray observatory
A large optical observatory
Visible and Ultraviolet
Visible & Radio
Microwave & Radio
Ultraviolet & Infrared
X-ray & Gamma-ray
The electron makes the transition from energy level 3 to energy level 2.
The electron makes the transition from energy level 2 to energy level 3.
The electron makes the transition from energy level 2 to energy level 1.
The electron makes the transition from energy level 1 to energy level 2.
The electron makes the transition from energy level 3 to energy level 4.
Lack of chromatic aberration
Shorter length for the same aperture size
Lighter weight for larger apertures
All of the above are valid reasons
The solar wind
The early universe
Brown dwarf stars
The absolute zero temperature.
The ground state.
The ionization level.
Responsible for Doppler shifts.
The energy level from which the Paschen Series of hydrogen originates.
Will not penetrate Earth's atmosphere and reach the ground.
Has a wavelength that is longer than the visible light emitted by the star.
Has a wavelength that is shorter than the X-rays emitted by the star.
A and b
B and c
A bright (emission) line
A dark (absorption) line
A bright (emission) line
Photons with longer wavelengths have lower frequencies
Radio wave photons have shorter wavelengths than gamma ray photons
X-rays can be transmitted through the atmosphere around the world
All of the above are true
All of these determines the element
None of these determines the element
Infrared telescopes only need to get above the ozone layer.
Infrared photons are quite energetic.
Infrared sources are very bright.
Infrared telescopes are not very heavy.
Infrared radiation is absorbed low in Earth's atmosphere by CO2 and water vapor.
Zero degrees Celsius.
The temperature at which atoms have no remaining energy from which we can extract heat.
The temperature at which water freezes.
Both a and c
None of the above
The solar wind
Will have similar luminosities but different masses
Will have similar spectral types but different luminosities
Will have different spectral types but similar luminosities
Will have similar masses but different distances
Distance and luminosity.
Distance and surface temperature.
Distance and color.
Luminosity and surface temperature.
Red, yellow, blue
Red, blue, yellow
Yellow, blue, red
Blue, red, yellow
The convective zone
The radiative zone
The heating in the chromosphere.
Shock waves in the corona.
The solar wind flowing away from the corona.
Rising gas below the photosphere.
Between 25 and 35 days.
About seven years.
About 11 years.
Much stronger than
Much weaker than
Slightly stronger than
The same as
Could be either, depending on their specific luminosities and distances.
Impossible to determine.
More massive star
Less massive star
More distant of the two stars
Being seen as two separate stars with a telescope
One star traveling a wiggly proper motion path across the sky
One star dimming abruptly as another passes in front of it
Pairs of absorption lines seen in the spectrum of what appears to be one star
All of the above
A liquid conducting layer in the interior
Fusion reactions in the core
This is a trick question. The solar magnetic field is primordial.
Star E is four times as big as star F
Star F is twice as big as star E
Star E is twice as big as star F
Star F is four times as big as star E
These are different names for the same property
Brightness is how we see a star; luminosity is how much light it emits
Luminosity is how we see a star; brightness is how much light it emits
Luminosity measures size; brightness measures temperature
2 hydrogens and 1 helium are fused into 1 carbon + energy
4 hydrogens are fused into 1 helium, 2 neutrinos + energy
2 protons and 2 neutrons are fused into 1 carbon + energy
2 heliums are fused into 1 carbon, 1 neutrino + energy
It must be larger than the Sun.
It must be smaller than the Sun.
It must be within 1000 parsecs of the Sun.
It must be farther away than 1000 parsecs.
Both a and b above.
Earth's orbit was longer.
The stars were farther away.
Earth moved slower along its orbit.
All of these
None of these