1) a conductor of rad r, length e and resistivity p has resistance R. what is the new resistance if it is stretched to 4 times its original length?
a) 1/16R b) 1/4R c) R d) 4R e) 16R
2) a small bulb is rated at 7.5W when operated at 125V. it has resistance in OHMS of?
a) .45 b)7.5 c) 17 d) 940 e) 2100
3) a small bulb is rated at 7.5W when operated at 125V. the tungsten filament has a temp coeff of resistivity a=4.5x10^-3/C. when the filament is hot and glowing its temp is seven times the room temp 20C. what is the resistance of the filament in OHMS at room temp.