Constants Eight bulbs are connected in parallel to a 220 V source by two long le

Question

Constants Eight bulbs are connected in parallel to a 220 V source by two long leads of total resistance 1.4 Part A If 270 mA flows through each bulb, what is the resistance of each? Express your answer to two significant figures and include the appropriate units R= 800 Previous Answers Correct Part B If 270 mA flows through each bulb, what fraction of the total power is wasted in the leads? Express your answer using two significant figures. Pwasted Submit Previous Ans ers Request Answer X Incorrect: Try Again; 15 attempts remaining

Explanation / Answer

From the given question,

voltage(V)=220 V

lead resistance=1.4 ohms

total current= 270*10^-3*8=2.16 A

voltage lost across leads= 2.16*1.4=3.024 V

voltage across bulbs= 220-3.024=216.976 V

resistance of each bulb= 216.976/(0.270)=800 ohms

part(B)

power lost in lead= i^2 R= 2.16^2*1.4=6.53 W

power lost in bulbs= 8*0.270^2*803=468.31 W

fraction of power lost=6.53/(6.53+468.31)=1/73

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