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Current Electricity Set-1

Test your knowledge on Current Electricity from Physics, Class 12.

Current Electricity is a cornerstone of Class 12 Physics, bridging the gap between static charges and the dynamic application of electrical energy in modern technology. This chapter provides a deep dive into the behavior of charge carriers in conductors, exploring fundamental concepts like drift velocity, Ohm's law, and the complex internal workings of electrochemical cells. Understanding these principles is essential for mastering both theoretical derivations and practical circuit analysis, which are frequently tested in the CBSE board examinations.

From a competitive standpoint, this chapter carries significant weightage. Mastery over Kirchhoff’s Rules, the Wheatstone bridge, and the temperature dependence of resistivity is crucial for solving numerical problems efficiently. This practice set is meticulously designed to align with the latest NCERT 2024-25 syllabus, focusing on conceptual clarity and the application of formulas to ensure students are well-prepared for both objective and descriptive questions in the final exams.

30

Minutes

30

Questions

1 / -0

Marking Scheme

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Questions in this Quiz

Q1: When a steady current flows through a metallic conductor of non-uniform cross-section, which of the following quantities remains constant along the conductor?

  • Current density

  • Drift speed

  • Electric field

  • Current

Q2: The drift velocity vdv_d of free electrons in a conductor is very small (of the order of few mm/smm/s). Yet, an electric bulb lights up almost instantly when the switch is turned on because:

  • Electrons move with the speed of light.

  • The electric field is established throughout the circuit almost instantly.

  • The electrons already present in the filament start moving.

  • Both (B) and (C).

Q3: A wire of resistance RR is stretched to double its original length. Its new resistance will be:

  • 2R2R

  • 4R4R

  • R/2R/2

  • R/4R/4

Q4: The relaxation time τ\tau in a conductor:

  • Increases with increase in temperature.

  • Decreases with increase in temperature.

  • Is independent of temperature.

  • Increases with the square of temperature.

Q5: The resistivity of a typical semiconductor like Germanium:

  • Increases with increase in temperature.

  • Decreases with increase in temperature.

  • Remains constant with temperature.

  • First increases then decreases.

Q6: A cell of emf EE and internal resistance rr is connected across an external resistance RR. The maximum power is delivered to the external circuit when:

  • R=rR = r

  • R=2rR = 2r

  • R=r/2R = r/2

  • R=0R = 0

Q7: Kirchhoff’s first law (Junction rule) ∑I=0\sum I = 0 is a consequence of the law of conservation of:

  • Energy

  • Momentum

  • Charge

  • Mass

Q8: Kirchhoff’s second law (Loop rule) ∑ΔV=0\sum \Delta V = 0 is a consequence of the law of conservation of:

  • Charge

  • Energy

  • Momentum

  • Angular momentum

Q9: The unit of mobility μ\mu is:

  • m2V−1s−1m^2 V^{-1} s^{-1}

  • mV−1s−1m V^{-1} s^{-1}

  • m2Vs−1m^2 V s^{-1}

  • mVs−1m V s^{-1}

Q10: The current density JJ is related to the electric field EE by the relation:

  • J=σEJ = \sigma E

  • J=ρEJ = \rho E

  • J=E/σJ = E / \sigma

  • J=σ/EJ = \sigma / E

...and 20 more questions.

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