current electricity........

[avid_reader]

Give reasons....
1.The electron drift speed is estimated to be only a few mm's .How can such a small speed account for instantaneous current.
2. Is a wire carrying current charged?Why or why not?


........A house fitted with 10 bulbs of 50W 200V each ,8fans consuming 0.5 ampere at 200V each and an electric iron having a resistance of 250 ohms. If the power supplied is at 200V and the cost of energy is Rs. 5 per KWh. Find the electricity bill for the month of june if all above appliances are used for 5 hours in a day........

[pkciit]

a wire carrying current is not nescessarily charged
because current in a wire is due to the flow of electrons
drifting from one end to another end

[sachinsethi]

here are the answers !!!
1. it is true tht the drift velocity is of the orders corresponding to a few mm/s .... however... in a wire (conductor).. there are electron throughout the length... as a result.. each electron gains this velocity and there is motion...
it may take time for an electron to travel the whole length of the wire.. but as there are electron throughout the length... the current is established instantaneously.

2. no. a wire is not charged... this is because the total no of electrons in the wire remains the same b4 and after the current is applied.. actually.. no od electrons entering = no of electrons exiting... and over any marcoscopic volume= charge = 0.

3. i think the answer should be Rs. 1095.
formula=
no. of Kwh = (n1*p1*t1 + n2*p2*t2 + n3*p3*t3)/1000.
convert resistance and current into power..
n= no. of units..
p = power
t = time

thanx !!! hope tht helped... plz verify the answers..

[avid_reader]

thanx a ton.....