Dc Circuit

1. The presence of electric current is only made known by the effect it produces. Three important effects are: a. he heating, el electric sh shock & generation c. ge generation, ch chemical & electric sh shock b. heating, magnetic & electric shock d. heating, magnetic & chemical 2. Out of the following, select the best conductor of electricity? a. polyethylene b. ceramic c. china clay d. graphite . !hich of the following conductors has the highest resistance? a. manganin b. nichrome c. constantan d. steel ". !hat is the si#e in s$uare millimeter is the cable 2%'(' si#e? a. 11).*%* b. 12*.*+% c. 112.%*% d. 12.") %.  copper copper bar - inch by " inches b y 2ft. f the resisti/ity of the copper bar is 1.+ ohm0cmf. !hat is the resistance of the copper bar? a. 1+.10*ohm b. 12%ohms c. .%2ohm d. ).%10%ohm *.  one meter rod of 2cm diameter is drawn until its resistance is 1times the initial resistance, its length afterward is? a. 1m b. 12.%m c. 1m d. %m +.  one meter of annealed copper 2.%cm in diameter is drawn until its resistance is 1 times the initial resistance, its diameter afterward is? a. .+3cm b. ."+cm c. .2%cm d. .1%cm ). 4uppose that you wish to fabricate a uniform wire out of 1gram of copper. The resistance of wire is to be .%ohm and if all of the copper are to be used, what will be the diameter of wire? 4pecific resistance is 1.+10)ohm0meter and mass density is ).321 kg5m. a. 2+6m b. 2)6m c. 2*6m d. 236m 3.  dc motor 127 has 1 rated current. The allowable /oltage drop of 8 of input /oltage. 9ind the maimum distance from the supply if the wire has a diameter of 1*mils and resisti/ity of wire is 1." ohm0cmf. a. %)ft b. 1*ft c. 1+)ft d. 2ft 1.  light bulb ha/ing a tungsten filament draws .% at 117. The The cold resistance of the filament is 2ohms at 2( with temperature coefficient of resistance resistance for tungsten at this temperature of .% per (. ;etermine the operating temperature of the bulb. a. 122( b. %2( c. 2%2( d. 22( 11. 11.  17 carbon filament lamp takes 1 when glowing with a filament temperature of 1*1%(. (alculate the momentary current when the lamp is first switched on in air temperature of 1%(. The temperature coefficient of resistance for carbon may be taken as 0.2*% per ( at 1%(. a. 1.+2 b. .*% c. .%) d. 1.3" 12. 9ind the work in k!h to lift 1 ton at height of %%ft for 1 sec. The motor gear efficiency is %18. a. .) b. ) c. .) d. ) 1.  2" /olt battery deli/ers 1% to a motor load in  minutes per day. !hat is the energy deli/ered per month in k!h? a. *.2 b. %." c. +.1 d. .1) 1".  certain certain process uses warm water at rate of 2liters per minutes. The water enters at electric heater at 2%( to %(. ssuming no heat losses, what is the wattage of the heater? a. %12% b. *2% c. 2"2 d. ")) 1%. t is a cell designed to produced electric current and can be recharged. a. secondary cell b. chemical cell c. electrolytic cell d. battery 1*. !hat is the watt0hour efficiency of storage battery? a. < ou output o/ o/er !< !< input in in re recharge c. ! < output ba based on on < in input in in re recharge b. !< outp output ut base based d on on < inp input ut in rech rechar arge ge d. < out outpu putt bas based ed on < out outpu putt in in rec recha harg rge e 1+.  127 battery has %0hr capacity. capacity. The internal resistance is .1ohm.  %ohm resistor is connected for % hours.