Three electric bulbs with a rated power of 45.60.75 W, designed to operate on a 220 V network

| June 19, 2021 | education

Three electric bulbs with a rated power of 45.60.75 W, designed to operate on a 220 V network, are connected in series in the circuit. What power does each light bulb consume with this type of connection at 220 V?

Formula for determining electrical power:
P = U² / R
Determine the resistance of the devices:
R1 = U² / P1 = 220² / 45 = 1075 Ohm
R2 = U² / P2 = 220² / 60 = 807 Ohm
R3 = U² / P3 = 220² / 75 = 645 Ohm
3. When connected in series, the amperage:
I = U / R total
I = U / (R1 + R2 + R3)
We have:
I = U / (R1 + R2 + R3) = 220 / (1075 + 807 + 645) = 0.087 A
Let’s determine the voltages on our devices:
U1 = I * R1 = 0.087 * 1075 = 93.6 V
U2 = I * R2 = 0.087 * 807 = 70.2 V
U3 = I * R3 = 0.087 * 645 = 56.2 V
Determine the power of the bulbs, after connecting in series:
P1 = U1² / R1 = 93.6² / 1075.6 = 8.14 W
P2 = U2² / R2 = 70.2² / 807 = 6.1 W
P3 = U3² / R3 = 56.2² / 645 = 4.9 W
Answer: 8.14 W, 6.1 W, 4.9 W.



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