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York College@ CUNY ASTR 101 Y Dr.I.E.Ekejiuba Fall2011

About how many stars are visible on a clear, dark night with the naked eye alone?

a few thousand

Into how many constellations is the celestial sphere divided?


What is the range of values for declination?

+90 to -90 degrees

How long is the precession cycle?

26,000 years

The places where the sun crosses the equator are called the?


What celestial line is a product of the earths orbit around the sun


A solar eclipse can only happen during a

perihelion passage of the sun

A lunar eclipse can only happen during a

new moon

Which of the following describes parallax?

It is inversely proportional to the distance to the star

A star with a large parallax

is a short distant from Earth

The Ptolemaic model probably persisted for all these reasons EXCEPT:

it was consistent with the doctrines of the Catholic Church

The Ptolemaic model of the universe:

explained and predicted the motions of the planets with deferents and epicycles

Scientists today do not accept the Ptolemaic model because:

the work of Tycho and Kepler showed the heliocentric model was more accurate

On which of these assumptions do Ptolemy and Copernicus agree?

all orbits must be perfect circles

A planet whose distance from the sun is 3 A.U. would have an orbital period of how many Earth-years?


Which was a contribution to astronomy made by Copernicus?

The planets move around the Sun in elliptical orbits

A fatal flaw with Ptolemy's model is its inability to predict the observed phases of

Mercury and Venus

Upon which point do Copernicus and Kepler disagree?

The orbit of the planets are ellipses, with one focus at the Sun

What does Kepler's third law imply about planetary motion?

Planets further from the Sun orbit at a slower speed than planets closer to the Sun

The place in a planet's orbit is closet to the Sun is called


The force of gravity varies with

both product of the two masses and inverse square of the distance separating the two bodies

How much stronger is the gravitational pull of the sun on Earth, at 1AU, than it is on Saturn at 10 AU


If a wave's frequency doubles, its wavelength

is halved

Which of these is constant for ALL types of electromagnetic radiation in a vacuum?


The two forms of electromagnetic radiation that penetrate the atmosphere best are:

visible and radio waves

According to Wien's Law, if the surface temperature is increased by a factor of 2, its peak wavelength will

decrease by a factor of 2

Stefan's Law says:

that if the Suns temperature were doubled, it would give off 16 times more energy

The three laws dealing with the creation of various spectra are due to:


The particle which adds mass but no charge to the atomic nucleus is the


Which of these is the classic continuous spectrum?

a rainbow

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