Question

two lamps one rated 100w 220v and other 60w at 220v are connected in parallel to electric mains supply what current is draen from the line if the supply voltage is 220v?

Answer 1

Power = P = 100 W
Voltage = V = 220v
Resistance = R

P = V²/R
100 = 220 ×220/R
R  = 220 × 220/100
     = 484 Ω
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Power = P = 60 W
Voltage = V = 220v
Resistance = R

P = V²/R
60 = 220 × 220/R
R = 220× 220/60
    = 806.7 Ω
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As the resistors are connected in parallel , 
total resistance = 1/R

1/R = 1/484 + 1/806.7
      =  806.7 + 484/484×806.7
      = 1290.7/390442.8
R = 390442.8/ 1290.7 = 302.5 ohms
    
  Total resistance = 302.5 Ω


I = current

V = IR
220 = I × 302.5

I = 220/302.5
   = 0.73 A

The current drawn is 0.73 A

Answer 2

Answer:

Ur answer is pin with this

Explanation:

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