Two lamps are rated 40W and 220V each are connected in series. The total power dissipated in both lamps is
10W
20W
40W
80W
None of the above
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P = V^2/R
R = V^2/p = (220x220)/40
R = 1210ohms
Total Rs = R1 + R2
Total Rs = 1210 + 1210
Total Rs = 2420ohms
Total emf = V1+V2
Total emf = 220 + 220
Total emf = 440v
Total power dissipated
P = V^2/R
P = (440x440)/2420
P = 80w
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Power =v^2/r. Cross multiply to get r. R=v^2/p. 220^2/40=1210. Then substitute in p=v^2/r. 220^2/1210=40w series connection. R1+R2 =40+40=80w hope it helps
This is pure simple English. The question said “Each", 40W each. Simple add 40W to 40W and you get 80W. Thanks 
The solution given by My school Ai solution is different from what My school gave
myschool the answer is B
since the powers are in series u don't need to add.
it means they are receiving the same voltage.
u should have add if it in parallel
since they are both in series...
total voltage ÷ no of bulbs
40÷2 =20v
if it's parallel it will be multiplication
so why are we not using the 220v, please someone should help me.i don't understand this one
The selected answer is actually wrong, power connected in series are treated as resistance connected in parallel, verse versa e.g
40×40/80 =20. if it were to be parallel, then it would literally be added together
Just do ur research and verify.
