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THE LIGHT SOURCE
Practical Questions
(For answer to each question see statement of corresponding number in Chapter XIV)
1. What two light sources are employed in projection?
2. Is there a wide variation in available arc light sources?
3. Is special treatment of each arc light source essential to best results ?
4. How is an electric arc formed ?
5. What becomes of the carbon particles?
6. How is a conductor established between the incandescent carbon tips?
7. What is the "crater" of an electric arc? How is it formed?
8. What is the temperature of the crater floor?
9. How does an electric arc crater floor compare in brilliancy with other light sources?
10. How can the brilliancy be further increased ?
Carbons, page 361
11. What is a "carbon"? How are carbons classified?
12. What qualities must projection carbons possess?
13. Do carbon cores contain chemicals?
14. Must carbons be free from moisture when used?
15. For what reasons was carbon selected as the base of electric arc electrodes?
16. At what temperature is carbon volatilized — transformed into gas ?
17. What is the luminosity of carbon at the temperature of volatilization ?
18. Does the conductivity of carbon increase as temperature is increased ?
19. Is carbon core conductivity higher than that of the surrounding shell?
20. Are carbons made in all lengths required for arc lamps?
21. Describe the general process of making a carbon.
22. What is the source of the most intense light in each of the three general types of projection arcs?
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