Electricity 



229 



FlG. 130. How can the electric iron be used after one wire has been cut? 



Application 56. A man wanted to change the location 

 of the wiring in his cement-floored garage. While he was 

 working, would it have been best for him to stand on the 

 bare cement floor, on a wire mat, on an old automobile tire, 

 on a wet rug, or on some skid chains that were there ? 



Inference Exercise 



Explain the following : 



331. An ungreased wheel squeaks. 



332. Lightning rods extend into the earth. 



333. A banjo player moves his fingers toward the drum end of the 



banjo when he plays high notes. 



334. When the filament breaks, an electric lamp will no longer glow. 



335. An inverted image is formed by the lens of a camera. 



336. A blown-out fuse may be replaced temporarily with a hair- 



pin or with a copper cent. 



337. Sparks fly when a horse's shoe hits a stone. 



338. A room requires less artificial light if the wall paper is light 



than if it is dark. 



339. Phonographs usually have horns, either inside or outside. 



340. An electric car needs only one wire to make it go. 



SECTION 37. Resistance. 



What makes an electric heater hot ? 



Why does lightning kill people when it strikes them? 



What makes an electric light glow ? 



