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Concepts Of Physics MCQ Edition [Volume 2]PhysicsThermal and Chemical Effects of Electric Current

A heater coil has a specification of 250 V , 500 W . Determine the resistance of the coil. Additionally, what will be the resistance of a 1000 W coil designed to operate at the same voltage?

Options

  1. A250 , 125
  2. B62.5 , 125
  3. C125 , 62.5
  4. D125 , 250

Correct answer

C. 125 , 62.5

Step-by-step solution

The power of a heater coil is given by the relation P = V^2 R . Rearranging for resistance, R = V^2 P . For the first coil with V = 250 V and P = 500 W : R₁ = 250^2 500 = 250 250 500 = 250 2 = 125 For the second coil with V = 250 V and P = 1000 W : R₂ = 250^2 1000 = 250 250 1000 = 62500 1000 = 62.5 The resistances are 125 and 62.5 respectively.

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