NEETPhysicsCurrent ElectricityMCQ+4 / −1
The resistances of the four arms P, Q, R and S in a Wheatstone's bridge are 10 ohm, 30 ohm, 30 ohm and 90 ohm, respectively. The e.m.f. and internal resistance of the cell are 7 volt and 5 ohm respectively. If the galvanometer resistance is 50 ohm, the current drawn from the celll will be
- A0.1 A
- B2.0 A
- C1.0 A
- D0.2 A
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Correct answer: D
From the question, total resistance of Wheatstone bridge is:
(40) × (120)/(40 + 120) = 30
Now the current through the cell is:
= 7V/(5+30) = (1/5)A = 0.2A
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