Two lamps, one rated 100 W at 220 V, and the other 60 W at 220 V, are connected in parallel to electric mains supply. What current is drawn from the line if the supply voltage is 220 V?
The total current drawn from the line is 160/220 A or approximately 0.727 A.
Explanation
This question tests the understanding of parallel connections and the relationship between power, voltage, and current. In parallel connection, the voltage across each appliance remains the same as the supply voltage (220 V). The power formula P = VI is used to find current for each lamp, and since currents add up in parallel, total current is the sum of individual currents.
Solution Steps
Step 1: For parallel connection, voltage across each lamp = Supply voltage = 220 V
Step 2: Using the formula P = VI, we get I = P/V
Step 3: Current drawn by Lamp 1 (100 W): I₁ = P₁/V = 100 W / 220 V = 100/220 A
Step 4: Current drawn by Lamp 2 (60 W): I₂ = P₂/V = 60 W / 220 V = 60/220 A
Step 5: In parallel connection, total current = I₁ + I₂ = 100/220 + 60/220 = 160/220 A
Step 6: Therefore, total current drawn = 160/220 A = 8/11 A 0.727 A