The Schwarzschild radius of a black hole is that radial distance ...

[schs14]

The Schwarzschild radius of a black hole is that radial distance from the center of a sphere within which not even light can escape.
 
  It was first discovered mathematically by Schwarzschild in 1916 after Einstein published his general relativity theory. It can be calculated from a star's mass M as: R = 2GM/c2. Take the radius of both stars A and B as the Schwarzschild radius. If the mass of star A is twice as much as the mass of star B, the average density of star A, compared to star B will be A)
 
  the same.
  B)
 
  twice as much.
  C)
 
  half as much.
  D)
 
  four times as much.
  E)
 
  one-fourth as much.

Question 2

The reason the position of a particle cannot be specified with infinite precision is the
 
  A)
 
  coherence principle.
  B)
 
  exclusion principle.
  C)
 
  uncertainty principle.
  D)
 
  photoelectric effect.
  E)
 
  principle of relativity.

[olderstudent]

Answer to Question 1

E

Answer to Question 2

C

[schs14]

Both answers were spot on, thank you once again

[olderstudent]

Great! Please up vote