Are these practice questions for Current Electricity based on the CBSE pattern?

Yes. Every practice question is modeled on the CBSE Class 12 - Science Physics exam pattern — including MCQs, assertion-reason questions, and short-answer formats that frequently appear in CBSE papers.

Are the practice questions for Current Electricity free?

Yes. Every chapter includes free practice questions for Class 12 - Science students to get you started.

What types of questions are included?

The practice set for Current Electricity mainly includes MCQs and CBSE-style short-answer questions, with instant feedback on each answer. For full-length textbook practice, use the NCERT Solutions page.

Are the practice questions suitable for board exam preparation?

Yes. The questions test the same concepts and depth that CBSE asks in board exams. After finishing, also solve the NCERT and NCERT Exemplar exercises for Current Electricity for full coverage.

How many practice questions are there for Current Electricity?

The number scales with chapter length and concept density. Each chapter typically has 15-50 practice questions across MCQ and short-answer formats.

Current Electricity Class 12 Physics Practice Questions with Answers

easy

Propose a material mentioned in the chapter that would be ideal for constructing wire-bound standard resistors for laboratory use and justify your choice based on its resistivity-temperature characteristics.

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easy

Define electric current and name its SI unit.

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easy

A battery with an emf of

6

V and an internal resistance of

0.5 \, \Omega

is connected to an external resistor of

5.5 \, \Omega

. Calculate the terminal voltage of the battery.

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easy

Examine why alloys like manganin and constantan are used for making standard resistors.

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easy

Justify why electric current is considered a scalar quantity, even though it is often represented with an arrow in circuit diagrams.

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easy

Define resistivity of a material and state its SI unit.

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easy

Identify the primary charge carriers responsible for current in (a) metals and (b) electrolytic solutions.

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easy

Define the internal resistance of an electric cell.

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easy

Recall the mathematical statement of Ohm's law.

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easy

A heating element is rated

2100

W at

230

V. Calculate the resistance of the element and the current it draws.

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easy

Demonstrate that the unit of mobility (

\mu

) can be expressed as

\text{m}^2 \text{V}^{-1} \text{s}^{-1}

.

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easy

Propose a reason why connecting the terminals of a car battery (e.g.,

12

V emf,

0.05 \Omega

internal resistance) directly with a thick copper wire is extremely dangerous, using the concept of maximum current.

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medium

Two wires, one made of copper and the other of nichrome, have the same length and the same resistance. Analyze which wire is thicker and provide a justification based on their resistivities.

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medium

Describe the vector relationship between current density (j), conductivity (σ), and electric field (E).

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medium

Explain Kirchhoff's two rules for analyzing electrical circuits. Name the fundamental conservation laws on which these rules are based.

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medium

A carbon resistor has a resistance of

500 \, \Omega

at

20.0^{\circ}

C. Calculate its resistance at

80.0^{\circ}

C. The temperature coefficient of resistivity for carbon is

\alpha = -5.0 \times 10^{-4} \, (^{\circ}\text{C})^{-1}

.

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medium

Recall the balance condition for a Wheatstone bridge and draw a labelled circuit diagram.

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medium

List the factors on which the resistance of a conductor depends and recall the formula that relates them.

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medium

Define the temperature coefficient of resistivity,

\alpha

.

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medium

Compare the power loss in transmission lines when power is transmitted at

220

V versus

22,000

V. Assume the power to be delivered is

11

kW and the resistance of the transmission lines is

2.0 \, \Omega

.

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medium

A cell has an emf of

1.5

V and an internal resistance of

0.1 \Omega

. Recall the formula to find the maximum current it can provide and calculate this value.

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medium

Analyze the effect on the balancing length in a meter bridge experiment if the positions of the galvanometer and the cell are interchanged.

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medium

Examine why Ohm's law is not universally applicable to all conducting materials, providing an example of a non-ohmic device.

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medium

Two cells, one with emf

1.5

V and internal resistance

0.2 \, \Omega

, and the other with emf

2.0

V and internal resistance

0.3 \, \Omega

, are connected in parallel. Calculate the equivalent emf and equivalent internal resistance of the combination.

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medium

In a Wheatstone bridge circuit with resistors

P=10 \, \Omega

,

Q=20 \, \Omega

,

R=15 \, \Omega

, and

S=30 \, \Omega

, a battery of

5

V is connected across the bridge. Calculate the current drawn from the battery.

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medium

Recall the basic formula for electric power (

P

) dissipated in a conductor. List two other forms of this formula using Ohm's Law.

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medium

Critique the statement: "Ohm's law,

V=IR

, is a fundamental law of nature applicable to all materials."

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medium

For the circuit shown in Figure 3.17 of the source document, create a set of three independent equations using Kirchhoff's rules that would allow you to solve for the currents

I_1

,

I_2

, and

I_3

. Justify the choice of loops.

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medium

You are given two copper wires of the same length, but wire A has a diameter twice that of wire B. Design a simple experiment to prove which wire has lower resistance and justify which wire would be a better choice for a heating element.

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medium

Formulate a mathematical model to justify why transmitting electrical power at high voltage is more efficient. Derive the expression for power loss and explain its dependence on transmission voltage.

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medium

Explain the term 'drift velocity' of free electrons in a metallic conductor.

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medium

Propose a modification to the standard series combination of two cells with emfs

\varepsilon_1

and

\varepsilon_2

(where

\varepsilon_1 > \varepsilon_2

) and internal resistances

r_1

and

r_2

, such that the equivalent emf of the combination is

\varepsilon_1 - \varepsilon_2

. Justify your proposal.

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medium

A wire of resistance

R

is stretched to double its original length. Assuming the volume and resistivity of the material remain constant, calculate the new resistance of the wire in terms of

R

.

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medium

Evaluate the claim that the drift velocity of electrons is solely responsible for the speed at which a light bulb turns on when a switch is closed.

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hard

For the circuit shown, apply Kirchhoff's rules to solve for the currents

I_1

,

I_2

, and

I_3

flowing through the resistors

R_1=10\, \Omega

,

R_2=5\, \Omega

, and

R_3=20\, \Omega

. The batteries have emfs

\varepsilon_1 = 6

V and

\varepsilon_2 = 12

V.

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hard

Explain the terms electromotive force (emf) and terminal voltage of a cell. Describe the condition under which the terminal voltage is equal to the emf.

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hard

Summarize the effect of increasing temperature on the resistivity of (a) metals, and (b) semiconductors. Provide a brief reason for the behavior in metals.

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hard

Evaluate the effect of increasing temperature on the conductivity of a semiconductor versus a metal. Justify the difference in their behavior using the formula

\sigma = \frac{ne^2\tau}{m}

.

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hard

Formulate a set of Kirchhoff's rule equations for the Wheatstone bridge circuit shown in Figure 3.18 of the source document when it is unbalanced (

I_g \neq 0

). Use these equations to derive the balance condition

\frac{R_2}{R_1} = \frac{R_4}{R_3}

when

I_g

is set to zero.

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hard

A student proposes a circuit with three identical cells, each with emf

\varepsilon

and internal resistance

r

. To get maximum current through an external resistor

R

, they suggest connecting all cells in parallel. Evaluate this proposal for two distinct cases: (a)

R \gg r

and (b)

R \ll r

.

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hard

Calculate the drift velocity

v_d

of electrons in an aluminum wire with a cross-sectional area of

2.5 \times 10^{-6} \text{ m}^2

carrying a current of

5

A. Assume one conduction electron per atom. The density of aluminum is

2.7 \times 10^3 \text{ kg/m}^3

and its atomic mass is

27.0

u.

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hard

Design an experiment using a Wheatstone bridge to determine the temperature coefficient of resistivity,

\alpha

, for an unknown metallic wire. Formulate the necessary equations and justify the procedure.

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hard

Design a simple platinum resistance thermometer. Given that the resistance of a platinum wire is

R_0

at the ice point (

0^\circ\text{C}

) and

R_{100}

at the steam point (

100^\circ\text{C}

), formulate a linear equation to determine an unknown temperature

t

(in Celsius) from a measured resistance

R_t

. Justify the assumption of linearity and evaluate its limitations.

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hard

Critique the simple model for electron drift velocity,

v_d = \frac{eE\tau}{m}

, by identifying at least two major assumptions made in its derivation and explaining their implications on the model's accuracy.

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Current ElectricityClass 12 Physics Practice Questions