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NEETPhysicsCurrent Electricity

In a single-loop circuit, three batteries are connected in series such that their polarities aid each other in driving the current. The electromotive forces (EMFs) of the first two batteries are 5 V and 3 V , while the EMF of the third battery is E . If the total resistance of the circuit is 4 and a steady current of 3 A flows through it, what is the value of the unknown EMF E ?

Options

  1. A20 V
  2. B12 V
  3. C10 V
  4. D4 V

Correct answer

D. 4 V

Step-by-step solution

Since the three batteries are connected in series and aid each other, the net EMF of the circuit is the sum of their individual EMFs. E_ net = 5 V + 3 V + E = (8 + E) V According to Ohm's law for a complete loop, the current I is given by: I = E_ net R_ total Substituting the given values: 3 = 8 + E 4 12 = 8 + E E = 4 V Answer: 4 V

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