A 100W bulb operates at 220V. What is the resistance of the bulb? (2021)

Practice Questions

Q1
A 100W bulb operates at 220V. What is the resistance of the bulb? (2021)
  1. 484Ω
  2. 220Ω
  3. 110Ω
  4. 100Ω

Questions & Step-by-Step Solutions

A 100W bulb operates at 220V. What is the resistance of the bulb? (2021)
  • Step 1: Identify the power (P) of the bulb, which is 100W.
  • Step 2: Identify the voltage (V) at which the bulb operates, which is 220V.
  • Step 3: Use the formula for power: P = V^2 / R, where R is the resistance.
  • Step 4: Rearrange the formula to solve for R: R = V^2 / P.
  • Step 5: Substitute the values into the formula: R = (220V)^2 / 100W.
  • Step 6: Calculate (220V)^2, which equals 48400.
  • Step 7: Divide 48400 by 100W to find R: R = 484Ω.
  • Ohm's Law and Power Formula – Understanding the relationship between power, voltage, and resistance in electrical circuits.
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