Free Current Electricity MCQs with Answers
1,052 Current Electricity MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Steady current relates charge flow to potential difference, resistance and resistivity, including how temperature changes a conductor's resistance. Sources with internal resistance have terminal voltage below their emf when delivering current, and maximum power output occurs under a specific load condition rather than at zero resistance.
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- A. iron
- B. tungsten
- C. silver
- D. copper
Explanation: Copper is preferred for connecting wires because it has low resistivity, so it carries current with little energy loss, and it is much…
Correct answer: copper- A. finite
- B. infinite
- C. zero
- D. changes with every conductor
Explanation: Below its critical temperature, a superconductor allows charge to flow without resistance, so its resistance is zero ohm.
Correct answer: zero- A. remains the same
- B. is doubled
- C. is halved
- D. becomes zero
Explanation: Resistivity is a property of the material, represented by ρ in R = ρL/A, so cutting the wire changes its length and resistance but not its…
Correct answer: remains the same- A. nature of conductor
- B. dimension of conductor
- C. physical state of the conductor
- D. all of above
Explanation: Resistance follows R = ρL/A, so it depends on the conductor's dimensions and material, while resistivity can also change with physical…
Correct answer: all of above- A. constantan
- B. nichrome
- C. copper
- D. tungsten
Explanation: Tungsten is used for bulb filaments because it has a very high melting point and can become white-hot without melting.
Correct answer: tungsten- A. will depend on its length
- B. will depend on its radius
- C. will depend on the type of material of the wire
- D. will depend on none of the above
Explanation: Specific resistance, or resistivity, is an intrinsic property determined mainly by the material and its temperature, not by the wire's…
Correct answer: will depend on the type of material of the wire- A. 100W
- B. 200W
- C. 60W
- D. all
Explanation: At the same supply voltage, R = V²/P, so the 60 W bulb has the greatest resistance and therefore the smallest filament cross-sectional…
Correct answer: 200W- A. resistance
- B. inductance
- C. conductivity
- D. flexibility
Explanation: Conductivity is the reciprocal of resistivity, σ = 1/ρ, and its SI unit is siemens per metre.
Correct answer: conductivity- A. infinite
- B. zero
- C. finite
- D. depends upon nature
Explanation: An ideal insulator does not allow current to flow, which is represented by infinite resistance.
Correct answer: infinite- A. very good conductor
- B. moderately good conductor
- C. an insulator
- D. no specific criterion available
Explanation: Conductance is the reciprocal of resistance, G = 1/R, so a very high conductance means the wire offers very little opposition to current…
Correct answer: very good conductor- A. ML-1T-2
- B. ML-2T-2
- C. MLT-2
- D. ML2T-2
Explanation: Elastic modulus is stress divided by strain, and strain has no dimensions.
Correct answer: ML-1T-2- A. be quadrupled
- B. be doubled
- C. be halved
- D. remain unchanged
Explanation: Drift velocity is proportional to the electric field, and for a wire of fixed length the electric field is proportional to the applied…
Correct answer: be doubled- A. Divider
- B. Shunt
- C. Multiplier
- D. None of these
Explanation: A shunt is a very low-resistance path connected in parallel to bypass part of the current around a component or measuring instrument.
Correct answer: Shunt- A. IR Drops
- B. Battery emf
- C. junction voltages
- D. both "1" and "2"
Explanation: Kirchhoff's second rule states that the algebraic sum of potential changes around a closed loop is zero, so the total battery emf equals…
Correct answer: both "1" and "2"- A. Metric system
- B. Metric or French system of units
- C. Metric or British system of units
- D. None of these
Explanation: The CGS system is based on centimetre, gram and second, and is a metric system historically called the French system.
Correct answer: Metric or French system of units- A. one electron
- B. 10 -6 electrons
- C. 106 electrons
- D. 6.25 x 10^12 electrons
Explanation: Current is charge transferred per second, so the number of electrons per second is I/e = 1 x 10^-6 coulomb per second ÷ 1.6 x 10^-19…
Correct answer: 6.25 x 10^12 electrons- A. Protons
- B. Electrons
- C. Metal atoms
- D. Metal ions
Explanation: In a solid metal, positive ions remain fixed in the crystal lattice while loosely bound electrons can drift through the conductor.
Correct answer: Electrons- A. Electric current
- B. Electric charge
- C. Plane angle
- D. Amount of substance
Explanation: Electric charge is derived from electric current and time: Q = It, so its SI unit is coulomb = ampere second.
Correct answer: Electric charge- A. 4 volt
- B. 5 volt
- C. 2 volt
- D. 0.4 volt
Explanation: Using Ohm's law, the potential difference is V = IR = (0.020 A)(100 Ω) = 2.0 V.
Correct answer: 2 volt- A. very low damping
- B. very high damping
- C. no damping at all
- D. radial field disintegration
Explanation: A galvanometer uses low damping so even a small current can produce a noticeable deflection, although the pointer may take longer to…
Correct answer: very low damping