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JEE Main202227 Jul 2022Morning ShiftPhysicsAlternating CurrentActual

A direct current of 4 A and an alternating current of peak value 4 A flow through resistance of 3 Ω and 2 Ω respectively. The ratio of heat produced in the two resistances in same interval of time will be :

Options

  1. A3 : 2
  2. B3 : 1
  3. C3 : 4
  4. D4 : 3

Correct answer

B. 3 : 1

Step-by-step solution

Heat produced in resistor when direct current flows is H 1 = i 2 R 1 t H 1 = 4 2 3 t = 16 3 t Heat produced in resistor when alternating current flows is H 2 = i rms 2 R 2 t                                 i rms = i 0 2 H 2 = i 0 2 2 R 2 t H 2 = 4 2 2 × 2 t = 16 t Thus, the ratio is H 1 : H 2 = 3 : 1

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