This topic contains a solution. Click here to go to the answer
« previous next »

Author Question: Why are most large telescopes reflectors, not refractors? A) Large lenses deform under their own ... (Read 80 times)

future617RT

  • Hero Member
  • *****
  • Posts: 543
on: Jul 27, 2018
Why are most large telescopes reflectors, not refractors?
 
  A) Large lenses deform under their own weight, but mirrors can be supported.
  B) Large mirrors need only one optical surface, achromats four surfaces to grind.
  C) Reflectors do not suffer from chromatic aberration like refractors do.
  D) Large, very clear lenses are harder to cast than more tolerant mirror blanks.
  E) All of the above are correct.

Question 2

How can we determine the reflectivity of an asteroid?
 
  A) by taking a photograph of it
  B) by measuring its mass and radius
  C) by comparing its brightness in visible light to its brightness in infrared light
  D) by where it is located in the asteroid belt


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

sarahccccc

  • Sr. Member
  • ****
  • Posts: 318
Reply #1 on: Jul 27, 2018
Answer to Question 1

E

Answer to Question 2

C


future617RT

  • Member
  • Posts: 543
Reply 2 on: Jul 27, 2018
Great answer, keep it coming :)

nyrave

  • Member
  • Posts: 344
Reply 3 on: Yesterday
Wow, this really help

« previous next »
 

Did you know?

As many as 20% of Americans have been infected by the fungus known as Histoplasmosis. While most people are asymptomatic or only have slight symptoms, infection can progress to a rapid and potentially fatal superinfection.

Did you know?

As of mid-2016, 18.2 million people were receiving advanced retroviral therapy (ART) worldwide. This represents between 43–50% of the 34–39.8 million people living with HIV.

Did you know?

Fungal nail infections account for up to 30% of all skin infections. They affect 5% of the general population—mostly people over the age of 70.

Did you know?

When Gabriel Fahrenheit invented the first mercury thermometer, he called "zero degrees" the lowest temperature he was able to attain with a mixture of ice and salt. For the upper point of his scale, he used 96°, which he measured as normal human body temperature (we know it to be 98.6° today because of more accurate thermometers).

Did you know?

Autoimmune diseases occur when the immune system destroys its own healthy tissues. When this occurs, white blood cells cannot distinguish between pathogens and normal cells.

GI series. (a) Upper GI series begins with a barium swallow, barium shake, or barium meal. (b) Lower GI series. (a) Upper GI series begins with a barium swallow, barium shake, or barium meal. (b) Lower
Anatomy of the large intestine Anatomy of the large intestine
The 10-m Keck Telescopes The 10-m Keck Telescopes
Grazing Incidence X-ray Telescopes Grazing Incidence X-ray Telescopes
Do you know what that large object in the center of the photo is? In the 1920s, 30s, and 40s, ... Do you know what that large object in the center of the photo is? In the 1920s, 30s, and 40s, ...
The presence of large areas of methane hydrate The presence of large areas of methane hydrate
Video: Calvin Cycle Explained!

For a complete list of videos, visit our video library