Current ElectricityNEET MCQs with solutions
Current Electricity covers Ohm's law, resistivity, Kirchhoff's laws, Wheatstone bridge, meter bridge, potentiometer and electrical power. NEET tests circuit analysis using Kirchhoff's laws, resistor combinations, Wheatstone bridge balance condition and potentiometer sensitivity — one of the most numerical-heavy chapters.
- Class
- 12 Physics
- Free on this page
- 24 questions
- In the RankUp app
- 585 questions
- ELITE questions
- 44
- NCERT topics
- 14
Practise 24 questions
Tap an option to check it. Questions from every NCERT topic in this chapter, from easy to hard.
Q1Mixed Revision
The drift velocity of electrons in a conductor increases when:
Not quite — the answer is B.
vd = eEτ/m; increasing E directly increases drift velocity. Increasing temperature reduces relaxation time τ, so drift velocity decreases despite higher thermal energy.
Q2Grand Test
A conductor has resistivity ρ at temperature T. If the temperature increases, which correctly describes the change in resistivity for a metallic conductor?
Not quite — the answer is A.
For metals, increasing T amplifies lattice vibrations, increasing electron scattering and hence resistivity. Option B is wrong — free electron density is nearly constant in metals. Semiconductors show Option B behavior, a common mix-up.
Q3Drift Velocity, Mobility & Current Density
A copper wire carries a current of 4 A. If the number density of free electrons is doubled while all other parameters remain unchanged, the drift velocity becomes:
Not quite — the answer is D.
From vd = I/(neA), with I, e, A constant, vd is inversely proportional to n. Doubling n halves vd. Option B is the classic inversion trap — students confuse direct with inverse proportionality.
Q4Ohm's Law & Microscopic Explanation
Which of the following statements correctly represents Ohm's Law?
Not quite — the answer is B.
Ohm's Law: at constant temperature, V ∝ I for a metallic conductor, giving V = IR. Option A inverts the proportionality — the most common conceptual error. Option D confuses the roles of R and I.
Q5Combination of Resistors
Three resistors of 2 Ω, 3 Ω and 5 Ω are connected in series. Their equivalent resistance is:
Not quite — the answer is D.
Series: R_eq = R₁+R₂+R₃ = 2+3+5 = 10 Ω. Option C (8 Ω) traps students who add only two of the three resistors. R_eq in series is always greater than the largest individual resistance. Formula: R_eq = ΣR.
Q6Cells, EMF & Internal Resistance
A cell has emf 6 V and internal resistance 1 Ω. It supplies a current of 2 A. The terminal voltage is:
Not quite — the answer is B.
Terminal voltage V = E − Ir = 6 − (2×1) = 4 V. Option A arises from halving the EMF, a common arithmetic error. Formula: V = E − Ir.
Q7Wheatstone Bridge
The Wheatstone bridge is said to be balanced when which of the following conditions is satisfied?
Not quite — the answer is B.
At balance, no current flows through the galvanometer because both its terminals are at equal potential, giving P/Q = R/S. Option A and C are dimensionally plausible traps but have no physical basis in circuit analysis.
Q8Resistance, Resistivity & Conductivity
A wire of length 2 m and cross-sectional area 4 × 10⁻⁶ m² has a resistance of 1 Ω. The resistivity of the material is:
Not quite — the answer is B.
ρ = RA/L = (1 × 4×10⁻⁶)/2 = 2×10⁻⁶ Ω·m. Option A traps students who use ρ = RL/A (inverted formula). Formula: ρ = RA/L.
Q9Meter Bridge
A metre bridge works on the principle of:
Not quite — the answer is B.
The metre bridge replicates the four-arm Wheatstone bridge topology — the wire forms two arms and the known and unknown resistances form the other two. At balance, P/Q = R/S is satisfied.
Q10Potentiometer
A potentiometer works on the principle that the potential drop along a uniform wire carrying a steady current is:
Not quite — the answer is B.
For a uniform wire with constant current, V = IRl/L, so V is directly proportional to length l. Equal lengths produce equal potential drops.
Q11Kirchhoff's Laws
Kirchhoff's Current Law (KCL) is based on the conservation of:
Not quite — the answer is A.
KCL states that the algebraic sum of currents at a junction is zero, which directly follows from conservation of charge — no charge accumulates at a steady-state junction. Option B (energy) is the basis of KVL, not KCL.
Q12Potentiometer Applications
A voltmeter connected across a source always reads less than the true emf. Which of the following correctly identifies why a potentiometer eliminates this error during calibration?
Not quite — the answer is B.
At balance, zero current flows from the source — terminal voltage equals true emf. A voltmeter always draws current, causing a drop Ir across internal resistance, reading terminal voltage instead of emf.
561 more questions on this chapter are waiting in the app
Every one with a detailed explanation, plus flashcards and chapter tests.
Get RankUp on Google PlayQ13Electric Current & Charge Flow
Which of the following statements is correct regarding electric current in a metallic conductor?
Not quite — the answer is A.
In metals, free electrons drift opposite to the applied electric field; positive ions stay fixed in the lattice. This directed electron drift constitutes conventional current opposite to electron flow.
Q14Temperature Dependence of Resistance
The R-T graph for a pure metallic conductor is best described as:
Not quite — the answer is A.
For metals, R = R₀(1+αΔT) with α > 0 gives a linear increase — a straight line with positive slope on an R-T graph. Option B (negative slope) is the semiconductor graph, the most common confusion. Formula: R = R₀(1+αΔT).
Q15Electric Current & Charge Flow
A conductor carries a current of 8 A for 25 s. The total number of electrons crossing any cross-section is closest to:
Not quite — the answer is B.
Q = It = 8 × 25 = 200 C. n = Q/e = 200 / 1.6 × 10⁻¹⁹ = 1.25 × 10²¹. Option A errors arise from using Q = I/t instead of Q = It.
Q16Electric Current & Charge Flow
Which of the following is correct about the nature of electric current as a physical quantity?
Not quite — the answer is C.
Current has magnitude and a sense of flow but does not obey the triangle law of vector addition at junctions — it follows algebraic (scalar) addition via KCL. Option A confuses sense of flow with vector nature.
Q17Electric Current & Charge Flow
Which of the following does NOT act as a charge carrier in a metallic conductor?
Not quite — the answer is C.
Positive ions in a metal are fixed in the crystal lattice and cannot drift. Only free (conduction) electrons move under an applied field. Options A, B, D all describe the same mobile electron population.
Q18Electric Current & Charge Flow
Consider the following statements regarding electric current: I. Current is the rate of flow of charge. II. Current is a vector quantity. III. The SI unit of current is the ampere. IV. A current can exist through a conductor without net charge on it. How many of the above statements are correct?
Not quite — the answer is D.
Statement I: correct (I = Q/t). Statement II: incorrect — current is a scalar. Statement III: correct. Statement IV: correct — steady current leaves conductor neutral. Three statements (I, III, IV) are correct.
Q19Electric Current & Charge Flow
The SI unit of electric current, the ampere, is defined as the flow of how much charge per second?
Not quite — the answer is B.
By definition, 1 ampere = 1 coulomb per second (1 A = 1 C/s), directly from I = Q/t. Options A, C, D use wrong multiples of coulomb, a common unit-confusion trap.
Q20Electric Current & Charge Flow
A current of 0.8 A flows through a conductor for 15 minutes. The total charge transferred is:
Not quite — the answer is C.
t = 15 × 60 = 900 s. Q = It = 0.8 × 900 = 720 C. Option A arises from using t = 600 s (forgetting ×60 conversion), a very common exam error.
Q21Electric Current & Charge Flow
In which of the following media do positive and negative ions BOTH act as charge carriers to produce electric current?
Not quite — the answer is A.
In electrolytes, cations move toward the cathode and anions toward the anode — both contribute to current. In metals only electrons carry charge. At 0 K semiconductors have no free carriers.
Q22Electric Current & Charge Flow
A wire carries 3 C of charge every 0.25 s. The current through the wire is:
Not quite — the answer is D.
I = Q/t = 3 / 0.25 = 12 A. Option A arises from I = Q × t (inverting the formula), a common algebraic slip that gives a tempting small value.
Q23Electric Current & Charge Flow
Two wires X and Y carry currents of 4 A and 6 A respectively into a junction. What is the current leaving the junction?
Not quite — the answer is C.
By KCL, total current leaving = total entering = 4 + 6 = 10 A. Option D (6 A) traps students who subtract rather than add the incoming currents.
Q24Electric Current & Charge Flow
As per the NCERT definition, the SI unit of electric current is defined in terms of:
Not quite — the answer is C.
NCERT defines I = Q/t; hence the ampere is based on charge flow rate. Options A and B involve secondary derived quantities and are not the defining relation.
ELITE question · AIR under 50 level
This chapter has 44 ELITE questions for students aiming at the very top. They are only in the app.
Unlock ELITE questions in the appKey Circuit Concepts
Quick revision: most questions in this chapter test these facts.
| Concept | Key Formula |
|---|---|
| Ohm's law | V = IR; R = ρL/A; resistivity depends on material and temperature |
| Series resistors | R_eq = R₁ + R₂; current same; voltage divides |
| Parallel resistors | 1/R_eq = 1/R₁ + 1/R₂; voltage same; current divides |
| Kirchhoff's laws | KCL: ΣI = 0 at junction; KVL: ΣV = 0 in closed loop |
| Wheatstone bridge | Balanced when P/Q = R/S; no current through galvanometer |
| Power | P = VI = I²R = V²/R; max power transfer when R_ext = r (internal resistance) |
What the app covers in this chapter
585 questions in total, each with a detailed explanation.
| Mixed Revision | 76 |
| Grand Test | 76 |
| Drift Velocity, Mobility & Current Density | 40 |
| Ohm's Law & Microscopic Explanation | 40 |
| Combination of Resistors | 40 |
| Cells, EMF & Internal Resistance | 40 |
| Wheatstone Bridge | 40 |
| Resistance, Resistivity & Conductivity | 39 |
| Meter Bridge | 39 |
| Potentiometer | 39 |
| Kirchhoff's Laws | 38 |
| Potentiometer Applications | 38 |
| Electric Current & Charge Flow | 20 |
| Temperature Dependence of Resistance | 20 |
Questions students ask
Is Current Electricity important for NEET?
Very important — it is one of the highest-weightage Physics chapters. Kirchhoff's laws, resistor combinations, Wheatstone bridge and potentiometer are tested every year.
Which topics should I revise first?
Master series and parallel resistor combinations, Kirchhoff's laws for circuit solving, Wheatstone bridge balance, meter bridge and potentiometer working, and power/energy calculations.
How many questions from this chapter are on RankUp?
The RankUp app has 585 questions on Current Electricity, including 44 ELITE questions. Every question has a detailed explanation.
