Concepts Of Physics MCQ Edition [Volume 2]PhysicsElectric Current in Conductors
In the circuit depicted in the figure, the battery has an electromotive force E of 4.3 V and an internal resistance r of 1.0 . The external resistance R is 50 . The resistances of the ammeter and the voltmeter are 2.0 and 200 , respectively. Determine the readings of the ammeter and the voltmeter in the given switch configuration.
Options
- A0.1 A , 4.3 V
- B0.1 A , 4.0 V
- C0.08 A , 4.0 V
- D0.08 A , 4.2 V
Correct answer
B. 0.1 A , 4.0 V
Step-by-step solution
Based on the given circuit diagram, the switch S connects the voltmeter in parallel with the external resistance R only. First, we calculate the equivalent resistance of the parallel combination of the resistor R and the voltmeter R_V : R_p = R R_V R + R_V Substituting the given values ( R = 50 , R_V = 200 ): R_p = 50 200 50 + 200 = 10000 250 = 40 This parallel combination is in series with the ammeter ( R_A = 2.0 ) and the internal resistance of the battery ( r = 1.0 ). The total equivalent resistance of the circu