Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
Concepts Of Physics MCQ Edition [Volume 2]
Exam
Concepts Of Physics MCQ Edition [Volume 2]
Subject
Physics
Chapter
Electric Current in Conductors

Concepts Of Physics MCQ Edition [Volume 2] · Physics · Electric Current in Conductors

In the circuit depicted in the figure, the battery has an...

In the circuit depicted in the figure, the battery has an electromotive force E\mathcal{E} of 4.3 V4.3 \text{ V} and an internal resistance rr of 1.0 Ω1.0 \text{ }\Omega. The external resistance RR is 50 Ω50 \text{ }\Omega. The resistances of the ammeter and the voltmeter are 2.0 Ω2.0 \text{ }\Omega and 200 Ω200 \text{ }\Omega, respectively. Determine the readings of the ammeter and the voltmeter in the given switch configuration.
In the circuit depicted in the figure, the battery has an electromotive force E of 4.3 V and an internal resistance r

Options

  1. A0.1 A0.1 \text{ A}, 4.3 V4.3 \text{ V}
  2. B0.1 A0.1 \text{ A}, 4.0 V4.0 \text{ V}
  3. C0.08 A0.08 \text{ A}, 4.0 V4.0 \text{ V}
  4. D0.08 A0.08 \text{ A}, 4.2 V4.2 \text{ V}

Correct answer

B. 0.1 A0.1 \text{ A}, 4.0 V4.0 \text{ V}

Step-by-step solution

Based on the given circuit diagram, the switch SS connects the voltmeter in parallel with the external resistance RR only.

First, we calculate the equivalent resistance of the parallel combination of the resistor RR and the voltmeter RVR_V:
Rp=R×RVR+RVR_p = \dfrac{R \times R_V}{R + R_V}
Substituting the given values (R=50 ΩR = 50 \text{ }\Omega, RV=200 ΩR_V = 200 \text{ }\Omega):
Rp=50×20050+200=10000250=40 ΩR_p = \dfrac{50 \times 200}{50 + 200} = \dfrac{10000}{250} = 40 \text{ }\Omega

This parallel combination is in series with the ammeter (RA=2.0 ΩR_A = 2.0 \text{ }\Omega) and the internal resistance of the battery (r=1.0 Ωr = 1.0 \text{ }\Omega). The total equivalent resistance of the circuit is:
Req=Rp+RA+rR_{eq} = R_p + R_A + r
Req=40+2.0+1.0=43 ΩR_{eq} = 40 + 2.0 + 1.0 = 43 \text{ }\Omega

The total current II flowing through the main circuit, which is also the reading of the ammeter, is given by Ohm's law:
I=EReqI = \dfrac{\mathcal{E}}{R_{eq}}
I=4.343=0.1 AI = \dfrac{4.3}{43} = 0.1 \text{ A}

The voltmeter measures the potential difference across the parallel combination RpR_p. This voltage VV is:
V=I×RpV = I \times R_p
V=0.1×40=4.0 VV = 0.1 \times 40 = 4.0 \text{ V}

Therefore, the ammeter reads 0.1 A0.1 \text{ A} and the voltmeter reads 4.0 V4.0 \text{ V}.

Answer: 0.1 A0.1 \text{ A}, 4.0 V4.0 \text{ V}
Practice Electric Current in Conductors on Quantrex Academy →

More from Electric Current in Conductors

The amount of charge passing through a cross-section of a wire in time t is given by Q(t)… Concepts Of Physics MCQ Edition [Volume 2]A discharge tube carries an electric current of 2.0 . Determine the amount of charge that… Concepts Of Physics MCQ Edition [Volume 2]The current flowing through a wire varies with time according to i = i_0 + α t , where… Concepts Of Physics MCQ Edition [Volume 2]A copper wire with a cross-section of 1.0 mm^2 carries a current of 1.0 A . Determine the… Concepts Of Physics MCQ Edition [Volume 2]An electron gun releases 2.0 × 10^ 16 electrons per second. Determine the electric… Concepts Of Physics MCQ Edition [Volume 2]The amount of charge passing through a cross-section of a wire in time t is Q(t) = At^2 +… Concepts Of Physics MCQ Edition [Volume 2]A uniform wire having a resistance of 100 Ω is melted and recast into a new wire whose… Concepts Of Physics MCQ Edition [Volume 2]Determine the required length of a copper wire having a cross-sectional area of 0.01 mm^2… Concepts Of Physics MCQ Edition [Volume 2] Full Electric Current in Conductors list All Concepts Of Physics MCQ Edition [Volume 2] PYQs