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NEETPhysicsCurrent Electricity

A cell of emf 6 V and internal resistance 1 is connected across an unknown external resistor. If the terminal voltage measured across the external resistor is 4 V , what is the electric power dissipated in the external resistor?

Options

  1. A12 W
  2. B8 W
  3. C16 W
  4. D24 W

Correct answer

B. 8 W

Step-by-step solution

The terminal voltage V of a discharging cell is given by the relation: V = E - Ir Substituting the given values E = 6 V , V = 4 V , and r = 1 : 4 = 6 - I(1) I = 2 A The power dissipated in the external resistor is the product of the terminal voltage across it and the current flowing through it: P = V I P = 4 2 = 8 W Answer: 8 W

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