BUCKNELL UNIVERSITY

Astronomy 101- Quiz #1











Name: __Solution February 4, 2000
 
 

Formulas and numbers that you may need:

Waves speed: v=fl, 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, 1nm=10-9 meter,

Figure 4-3, Page 44, in your text by Pasachoff may also be useful. (Note that in that figure 10A=1nm).
 
 

Answer ALL 10 questions:
 
 

1. What is your seat #: __________

2. String A is denser and tighter than string B. As a result the waves in string A are

a. compressive, whereas the waves in B are transverse

b. faster than the waves in B

c. slower than the waves in B

d. transverse, whereas the waves in B are compressive.
 
 

3. Waves in a puddle are made by plunging a stick in and out of the water every four seconds. What is the frequency of the waves?

  1. 0.025 meter per second
  2. 0.4 1/sec
  3. 0.25 Hz
  4. 3 sec
4. If a sound wave and a radio wave have with similar wavelength then
  1. the frequency of the sound wave will be higher
  2. the frequency of the radio wave will be higher
  3. the frequencies of both waves will be the same
5. Light with frequency 7.5 x 1014 Hz is

a. red

b. blue

c. invisible

d. orange

6. Light with 200 billionths of a meter distance between wave crests is

a. red

b. green

c. magenta

d. invisible
 
 

7. When you placed a diffraction grating ("spectrum glasses") next to your eye in class and looked towards a red Neon discharge arc you saw

a. X-rays

b. all the colors of the rainbow

c. that the color of the stars in the night sky is mostly red

d. some emission lines
 
 

8. The energy of which of the following photon is the smallest: A photon with frequency

  1. 101.1 MHz
  2. 4 x 1014 1/sec
  3. 1 x 1019 Hz
  4. 9 x 1020 1/sec

 
 

9. The number of emission lines coming from an atom with these 5 energy levels is:
 
 

Fourth excited state ____________________________ 7 eV

Third excited state ___________________________ 6.5 eV

Second excited state ____________________________ 5.3 eV

First excited state ____________________________ 3.7 eV
 
 

Ground state _____________________________0.0 eV

  1. 6
  2. 10
  3. 12
  4. 20
10. If you move at a very high speed towards a yellow traffic light you may see it as a

a. red traffic light

b. green traffic light

c. dimmer yellow traffic light

d. huge loudspeaker.