Q114 / 180 · NEET 2019 (All India) · Physics

In the circuits shown below, the readings of the voltmeters and the ammeters will be,

Figure

  • A
    V2>V1 and i1=i2
  • B
    V1=V2 and i1>i2
  • Correct answer
    C
    V1=V2 and i1=i2
  • D
    V2>V1 and i1>i2

Solution

For an ideal voltmeter, resistance is infinite RV=∞, so it will not draw any amount of current from the circuit and for ideal ammeter resistance is zero.

Then for the first figure R1=10 Ω, RV=∞ and both are in a parallel arrangement, so

1Req=1R1+1RV⇒1Req=110+1∞⇒Req = 10 Ω

and current in the first circuit is, i1=V1Req=1010= 1 A

So, for the first circuit, ammeter and voltmeter readings are V1=10 V, i1=1 A, respectively.

For the second figure voltmeter and resistant of 10 Ω are in series and also connected parallel to another resistant of 10 Ω. So, equivalent resistant is 

1R'eq=1R1+1R2+RV⇒1R'eq=110+110+∞=110+0=110⇒R'eq=10 Ω

∴ Current in the circuit is, i2=V2Req'=1010=1 A, 

∴ Ammeter and voltmeter readings for the second circuit is V2=10 V, i2=1 A

∴ For both the circuit is 
V1=V2=10 V, i1=i2=1 A 

Hence, the correct answer is option: 'C'.

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