AP EAMCET201825 Apr 2018Morning ShiftPhysicsCurrent ElectricityActual
In a potentiometer, a wire of length 10 m having resistance 50 Ω is used. A battery of 5 V and a resistor of 450 Ω are connected in series to the wire. If an unknown battery of emf ' E ' balances the potentiometer at 450 cm , then the value of E is
Options
- A0 . 225   V
- B1 . 25   V
- C2 . 25   V
- D0 . 0225   V
Correct answer
A. 0 . 225   V
Step-by-step solution
In the case of potentiometer null point is obtained when the current flowing from the battery E 1 should be equal to current drawn from the battery E 2 , ⇒ i 1 = i 2 ⇒ E 1 R w i r e + R = E 2 R B a l a n c e here, E 1 = 5   V , R w i r e =   50   Ω ,   R = 450   Ω   &   E 2 = E ⇒ 5 50 + 450 = E R B a l a n c e the value of R B a l a n c e is, R B a l a c n e = R w i r e × 450 1000 = 50 × 450 1000 ⇒ 5 50 + 450 = E 50 × 450 1000 &