High School

Lamps, one rated 100 W; 220 V, and the other 60 W; 220 V, are connected in parallel to an electric mains supply. Find the current drawn by the two bulbs from the line if the supply voltage is 220 V.

Answer :

Final answer:

The 100 W and 60 W lamps connected in parallel to a 220 V mains supply draw approximately 0.455 A and 0.273 A, respectively. The total current drawn by both bulbs is approximately 0.728 A.

Explanation:

The subjects addressed in the question are related to electricity and specifically the concept of power, current, voltage, and resistance in electrical circuits. These topics are typically covered in high school physics courses. The lamps mentioned in the question are connected in parallel to an electric mains supply with a voltage of 220 V, and the task is to calculate the total current drawn by the two bulbs.

To find the current drawn by each bulb, we use the formula for electric power (P) which is:

P = VI,

where V is the voltage and I is the current. Rearranging the formula to solve for I, we get:

I = P/V.

For the 100 W lamp:

I100W = 100 W / 220 V ≈ 0.455 A (Amps).

For the 60 W lamp:

I60W = 60 W / 220 V ≈ 0.273 A (Amps).

The total current drawn by both bulbs is the sum of the currents of each bulb since they are connected in parallel:

Itotal = I100W + I60W ≈ 0.455 A + 0.273 A ≈ 0.728 A (Amps).

Therefore, the two bulbs together draw approximately 0.728 A from the line.

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