Name & Seat #: _______Key___ March 3, 2000
 
 

Formulas and numbers that you may need:

Energy = mass x c^2

Waves speed: v=f l; Period: P=1/f

Photons energy: E=hf,

Doppler shift: Df/f=v/c

c = 3.0 x 10⁸ m/s; h=6.6 x 10-34 J*s; 1 A.U. = 1.5 x 10^11 meter

Intensity = Power/Area

Area of a sphere = 4 pi r^2; Volume of a sphere = (4/3) pi r^3

From the observer’s triangle: Tan (alpha/2) = D/2L
 
 

Answer ALL 10 questions:
 
 

1. A chunk of matter has a mass of 1kg. Assuming that all that matter is converted into energy, the energy given off is:

1. 1 Joule
2. 3 x 10^8 Joule
3. 9 x 10^16 Joule
4. 1.5 x 10^11 Joule

1. The strong force is

1. A repulsive force between protons
2. An attractive force between protons
3. The force responsible for changing protons into neutrons
4. An attractive force between all particles in the universe

1. Plasma is a state of matter in which

1. electrons are ionized from their "mother atoms"
2. protons and neutrons change into electrons and neutrinos
3. everything is a liquid, like water or blood plasma
4. antimatter atoms kept in magnetic confinement

1. Using the parallax method we may find

1. the distance across a river
2. the distance to the nearest stars
3. the distance to a nearby planet
4. all of the above

1. Observing a star in spring and then in fall we find that it moved 9.3 x 10^-5 degrees with respect to faraway stars. The distance to that star is roughly:

1. 100 000 A.U.
2. 10 thousand A.U.
3. 1 thousand A.U.
4. 1 million A.U.

1. The distance to a star may be found if we know the star’s power, and measure its intensity (same as brightness). The area in the formula Intensity = Power/Area is just

1. 4pi x the distance to the star
2. 4pi x (the distance to the star)^2
3. 4pi x (the radius of the star)^2
4. 4pi x the radius of the star

1. Stars form when gas clouds contract due to

1. the strong force
2. gravity
3. coherent radiation from interstellar masers
4. the pull between electrons and protons

1. As the gas clouds that form stars contract they may

1. become very cold, because of the decreased space they occupy
2. become electrically charged, because only the protons fall towards the middle
3. spin faster and faster, possibly resulting in planet formation
4. become red dwarfs

1. When a converging (lentil shaped)lens is placed at roughly the focal distance from a wall the image that you see is

1. upside down and right side stays right
2. upside down and right side on the left
3. in black and white
4. focused and right side up

1. The three stars in "Orion’s belt" are

1. white dwarfs
2. all M2 stars
3. at very different distances from earth
4. oriented this way because they are a part of a triple star system