Astro 1500 Exam review - Exam 1

If you double the diameter of a telescope, by how much does the resolving power increase?

• 2 times as powerful

• 1/2 times as powerful

• 1/4 times as powerful

• 4 times as powerful

Answer explanation

The resolving power would double! The angular resolution would get smaller, which means the resolving power is going up.

Everything else remaining the same, if you double a star's temperature, the luminosity increases by __ times.

• 4

• 8

• 16

• 32

Answer explanation

The equation for luminosity depends on T^4, so if T increases a factor of 2, Luminosity increases by (2)^4 = 16 times more

Which one of these is a DISADVANTAGE of a space-based telescope?

• Some parts of the EM spectrum are inaccessible

• It is cheap to get up there

• It is nearly impossible to repair

• Jupiter can block the light

Answer explanation

Other disadvantages include the price, the limited data transfer rate, and limited aperture size

Again, you double the diameter of the telescope. By how much does the light gathering power increase?

• 2 times as powerful

• 4 times as powerful

• 1/2 times as powerful

• 1/4 times as powerful

Answer explanation

Because the equation has R^2, the brightness power will increase 4 times as much

Earth's elliptical orbit around the sun explains which of these phenomena?

• Some seasons are warmer than others

• The sun is higher in the sky during some seasons

• 
  Some seasons are slightly shorter than others

• None of these phenomena has anything to do with the Earth's elliptical orbit

Answer explanation

Earth's elliptical orbit means in spends more time at certain positions around the sun, meaning whatever season it is at that time is ever so slightly longer.

Which of these powers of a telescope matters the least for astronomy purposes?

• Light Gathering Power

• Resolving Power

• Magnification Power

• Cost

Answer explanation

Magnification power doesn't really mean much for astronomy. Making something bigger doesn't correlate to making it clearer (better resolved)

What is the wavelength range for microwaves?

• 1 m - 30 m

• 400 nm - 700 nm

• 750 nm - 1 mm

• 1 mm - 30 cm

Answer explanation

Microwaves have a range from 1 mm to 30 cm. Remember the grapes.

Which of these should we NOT see in a geocentric model that we should see in a heliocentric one?

• Retrograde planetary motion

• The planet Neptune

• Parallax of stars

• Solar eclipses

Answer explanation

There would be no parallax in a geocentric model, because the earth is not moving.

Why are all major telescopes reflecting telescopes? (Not refracting)

• The weight of lens can cause refracting telescopes to warp

• It's cheaper to build a larger telescope

• Easier to manufacture

• All of the above

Answer explanation

Reflecting telescope are just easier to use for astronomy, though many small, cheaper, personal telescopes are refracting

What is the Copernican Revolution?

• An attempt by Copernicus to overthrow the Polish government

• The transition from a geocentric model to a heliocentric model

• The transition to choosing the simplest explanation as the most likely

• The transition from using thought and intuition to acquire knowledge to instead using empirical evidence

Answer explanation

Copernicus backed up his findings with evidence and fact, rather than trying to think really hard about it like the greeks did