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

Determine the charges on the four capacitors having capacitances 1...

Determine the charges on the four capacitors having capacitances 1 μF1 \text{ }\mu\text{F}, 2 μF2 \text{ }\mu\text{F}, 3 μF3 \text{ }\mu\text{F}, and 4 μF4 \text{ }\mu\text{F} as shown in the figure.
Determine the charges on the four capacitors having capacitances 1 , 2 , 3 , and 4 as shown in the figure.

Options

  1. A2 μC2 \text{ }\mu\text{C}, 8 μC8 \text{ }\mu\text{C}, 9 μC9 \text{ }\mu\text{C}, and 12 μC12 \text{ }\mu\text{C}
  2. B6 μC6 \text{ }\mu\text{C}, 12 μC12 \text{ }\mu\text{C}, 18 μC18 \text{ }\mu\text{C}, and 24 μC24 \text{ }\mu\text{C}
  3. C3 μC3 \text{ }\mu\text{C}, 6 μC6 \text{ }\mu\text{C}, 9 μC9 \text{ }\mu\text{C}, and 12 μC12 \text{ }\mu\text{C}
  4. D1 μC1 \text{ }\mu\text{C}, 4 μC4 \text{ }\mu\text{C}, 4.5 μC4.5 \text{ }\mu\text{C}, and 6 μC6 \text{ }\mu\text{C}

Correct answer

A. 2 μC2 \text{ }\mu\text{C}, 8 μC8 \text{ }\mu\text{C}, 9 μC9 \text{ }\mu\text{C}, and 12 μC12 \text{ }\mu\text{C}

Step-by-step solution

In steady state, capacitors act as open circuits, so no direct current flows through the branches containing only capacitors.

Let the potential of the negative terminal of the 6 V6\text{ V} battery be 0 V0\text{ V} and the positive terminal be 6 V6\text{ V}. The left vertical wire is at 6 V6\text{ V} and the right vertical wire is at 0 V0\text{ V}.

For the branch with 1 Ω1\text{ }\Omega and 2 Ω2\text{ }\Omega resistors, they are in series. The current through this branch is:
I1=61+2=2 AI_1 = \dfrac{6}{1 + 2} = 2\text{ A}

The potential at the node between the 1 Ω1\text{ }\Omega and 2 Ω2\text{ }\Omega resistors is:
V1=6−(2×1)=4 VV_1 = 6 - (2 \times 1) = 4\text{ V}

This node is connected to the node between the 1 μF1\text{ }\mu\text{F} and 2 μF2\text{ }\mu\text{F} capacitors, so the potential between these capacitors is also 4 V4\text{ V}.

The potential difference across the 1 μF1\text{ }\mu\text{F} capacitor is 6−4=2 V6 - 4 = 2\text{ V}. Its charge is:
q1=1 μF×2 V=2 μCq_1 = 1\text{ }\mu\text{F} \times 2\text{ V} = 2\text{ }\mu\text{C}

The potential difference across the 2 μF2\text{ }\mu\text{F} capacitor is 4−0=4 V4 - 0 = 4\text{ V}. Its charge is:
q2=2 μF×4 V=8 μCq_2 = 2\text{ }\mu\text{F} \times 4\text{ V} = 8\text{ }\mu\text{C}

For the branch with two 3 Ω3\text{ }\Omega resistors, they are in series. The current through this branch is:
I2=63+3=1 AI_2 = \dfrac{6}{3 + 3} = 1\text{ A}

The potential at the node between the two 3 Ω3\text{ }\Omega resistors is:
V2=6−(1×3)=3 VV_2 = 6 - (1 \times 3) = 3\text{ V}

This node is connected to the node between the 3 μF3\text{ }\mu\text{F} and 4 μF4\text{ }\mu\text{F} capacitors, so the potential between these capacitors is also 3 V3\text{ V}.

The potential difference across the 3 μF3\text{ }\mu\text{F} capacitor is 6−3=3 V6 - 3 = 3\text{ V}. Its charge is:
q3=3 μF×3 V=9 μCq_3 = 3\text{ }\mu\text{F} \times 3\text{ V} = 9\text{ }\mu\text{C}

The potential difference across the 4 μF4\text{ }\mu\text{F} capacitor is 3−0=3 V3 - 0 = 3\text{ V}. Its charge is:
q4=4 μF×3 V=12 μCq_4 = 4\text{ }\mu\text{F} \times 3\text{ V} = 12\text{ }\mu\text{C}

The charges on the four capacitors are 2 μC2\text{ }\mu\text{C}, 8 μC8\text{ }\mu\text{C}, 9 μC9\text{ }\mu\text{C}, and 12 μC12\text{ }\mu\text{C} respectively.

Answer: 2 μC2 \text{ }\mu\text{C}, 8 μC8 \text{ }\mu\text{C}, 9 μC9 \text{ }\mu\text{C}, and 12 μC12 \text{ }\mu\text{C}
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