Question

I need help with the awnsers

Answer 1

First of all, this was a bit garbled up, so it is sort of incomplete. 

You gave me a total of 43 words, and I only counted 41 slots on the crossword graph itself, which is problematic. 

I got as far as I could, but some of the words either weren't provided, or the spaces were made incorrectly for the length of these words. 

Across: 
2. (black / pitch) 
7. conservation 
9. radiation 
12. crest 
13 ? 
14. whatever you wrote 
15. dense 
18. ? (radiant)
19. ? (radiant)
20. amperes 
23. medium 
25. density 
26. ? 
30. resistance 
31. (pitch / black) 
34. voltage 
35. insulator 
38. amplitudes 
39. thermal 
40. ? 
41. wavelength 

Down: 
1. electromagnetic
3. (conduction/ convection) 
4. (convection/ conduction) 
5. (current/ radiation) 
6. heat 
7. chemical 
8. transverse 
10. energy 
11. nuclear 
12. circuit 
16. electrical 
17. electrons 
21. mechanical 
24. source 
28. ? 
32. rise 
33. MRS CHEN 
34. volts 
36. sound