Two lubricating air heaters with 1 kW power and 220 V voltage are connected in series and turned on into 220 V voltage circuit. What is sum of the heaters' power then?

Question

zyberg · Answer

I think that since in series circuit U = U_1 + U_2, and both heaters are the same we should have both of them using up 110 V? 
@ganeshie8

zyberg · Answer

Or maybe, since I = I_1 = I_2; P = UI; and P_1 = P_2; we find that P_1 / I _1 = P_2 / I_2; P / I = P / I; U_1 = U_2? and since U = U_1 + U_2; U = 2 * U_1;  U_1 = U/2?

zyberg · Answer

(Basicially wrote the same thing as I had said in words, this time with letters, not sure if it's the right reasoning tho)

ganeshie8 · Answer

Your reasoning is good. Here is the trick : 
Find the resistance of the heaters

ganeshie8 · Answer

They gave you power and the voltage, 
can you find the resistance offered by the heater ?

zyberg · Answer

P = U^2/R;
R = U^2 / P;
R_1 = 220^2 / 1000 = 48.4 Ohms;
R_2 = R_1.

ganeshie8 · Answer

Yes, next draw a rough diagram representing the circuit

zyberg · Answer

|dw:1474913008167:dw|