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Current Electricity — MCQs, Practice Questions & Numericals

Current Electricity — MCQs, Practice Questions & Numericals

Master Current Electricity through concept-based MCQs,
exam-style practice questions and numerical problems designed
for CBSE Class 12, NEET and JEE preparation.

CBSE Class 12
NEET Physics
JEE Main
Concept MCQs
Numericals

Current Electricity Learning Path


Master Hub


Theory & Formulas


You are here: MCQs, Practice Questions & Numericals

Practice Current Electricity the Smart Way

Reading formulas is only the first step. Real mastery comes from
applying those formulas to conceptual questions, circuit problems,
graphs and numerical situations.

This practice page is designed to move from
concept → formula → application → numerical → exam question.

What You Will Practice

  • Electric current and charge flow
  • Drift velocity and current density
  • Ohm’s law and V-I characteristics
  • Resistance and resistivity
  • Temperature dependence of resistance
  • Series and parallel resistor combinations
  • EMF and internal resistance
  • Cells in series and parallel
  • Kirchhoff’s junction and loop rules
  • Wheatstone bridge
  • Electrical power and energy
  • Mixed numerical problems

Quick Formula Revision Before the MCQs

I = Q / t
I = n A e vd
J = I / A = n e vd
V = IR
R = ρL / A
RT = R0[1 + α(T − T0)]
Rseries =
R1 + R2 + … + Rn
1/Rparallel =
1/R1 + 1/R2 + … + 1/Rn
V = ε − Ir
P = VI = I²R = V²/R
W = Pt = VIt

Tip:
Before solving a numerical, identify what is given,
what is required, and which physical law connects them.

Section A — Conceptual MCQs

1. Electric current through a conductor is defined as

  1. Charge multiplied by time
  2. Charge flowing per unit time
  3. Energy per unit charge
  4. Resistance per unit length
Answer: B
Electric current is the rate of flow of charge:
I = Q/t.

2. The SI unit of electric current is

  1. Coulomb
  2. Volt
  3. Ampere
  4. Ohm
Answer: C — Ampere

3. If the charge flowing through a conductor doubles
while the time remains unchanged, the current

  1. becomes half
  2. doubles
  3. becomes four times
  4. remains unchanged
Answer: B
Since I = Q/t, doubling Q doubles I.

4. Drift velocity of electrons in a metallic conductor is generally

  1. equal to the speed of light
  2. very small compared with random electron speeds
  3. zero whenever current flows
  4. independent of electric field
Answer: B

5. The relation between electric current and drift velocity
in a conductor is

  1. I = neA / vd
  2. I = nAevd
  3. I = nAvd / e
  4. I = A / (nevd)
Answer: B
The correct relation is
I = nAevd,
where n is the number density of charge carriers,
A is the cross-sectional area,
e is the magnitude of charge on each carrier,
and vd is the drift velocity.

6. According to Ohm’s law, for constant physical conditions

  1. V is proportional to I
  2. V is proportional to 1/I
  3. R is proportional to I
  4. R is proportional to V
Answer: A

7. The slope of a V-I graph for an ohmic resistor represents

  1. current
  2. charge
  3. resistance
  4. conductance
Answer: C
Slope = ΔV/ΔI = R.

8. Resistance of a uniform wire increases when its

  1. length decreases
  2. cross-sectional area increases
  3. length increases
  4. resistivity decreases
Answer: C
R = ρL/A.

9. Resistivity is primarily a property of

  1. the shape only
  2. the material and its physical condition
  3. the length only
  4. the cross-sectional area only
Answer: B

10. Two identical resistors connected in parallel have
an equivalent resistance

  1. equal to one resistor
  2. twice one resistor
  3. half the resistance of one resistor
  4. four times one resistor
Answer: C

11. In a series circuit, the same quantity through every
resistor is

  1. potential difference
  2. current
  3. power
  4. resistance
Answer: B

12. In a parallel combination, the same quantity across
each branch is

  1. current
  2. charge flow rate
  3. potential difference
  4. resistance
Answer: C

13. The terminal voltage of a cell supplying current I is

  1. V = ε + Ir
  2. V = ε − Ir
  3. V = Ir − ε
  4. V = ε/I
Answer: B

14. Kirchhoff’s junction rule follows conservation of

  1. energy
  2. momentum
  3. charge
  4. mass only
Answer: C

15. Kirchhoff’s loop rule is based on conservation of

  1. energy
  2. charge
  3. mass
  4. current only
Answer: A

Section B — Higher-Level MCQs

16. A wire is stretched to twice its original length
without change in volume. Its new resistance becomes

  1. R/2
  2. R
  3. 2R
  4. 4R
Answer: D
Constant volume gives A’ = A/2 and L’ = 2L.
Therefore R’ = ρ(2L)/(A/2) = 4R.

17. A resistor of resistance R carries current I.
Its power consumption is

  1. IR
  2. I²R
  3. R/I²
  4. I/R
Answer: B

18. If the potential difference across a fixed resistor
is doubled, its power becomes

  1. half
  2. double
  3. four times
  4. unchanged
Answer: C
P = V²/R.

19. An ideal ammeter has

  1. very high resistance
  2. zero resistance
  3. infinite capacitance
  4. very high inductance
Answer: B

20. An ideal voltmeter has

  1. zero resistance
  2. low resistance
  3. very high resistance
  4. negative resistance
Answer: C

21. The SI unit of resistivity is

  1. Ω
  2. Ω m
  3. Ω/m
  4. A/V
Answer: B — Ω m

22. For metallic conductors, resistance generally

  1. decreases with temperature
  2. increases with temperature
  3. is always zero
  4. is independent of temperature
Answer: B

23. A cell delivers maximum power to an external resistance when

  1. R = 0
  2. R = ∞
  3. R = r
  4. R = 2r
Answer: C
Maximum power transfer occurs when the external resistance
equals the internal resistance.

24. If n identical cells are connected in series in the
same orientation, their ideal total emf is

  1. ε/n
  2. ε
  3. nε
  4. n²ε
Answer: C

25. At a junction in a steady current circuit

  1. more charge accumulates continuously
  2. current entering equals current leaving
  3. voltage entering equals current leaving
  4. all currents must be equal
Answer: B

Section C — Numerical Practice

Numerical 1 — Electric Current

A charge of 60 C flows through a conductor in 20 s.
Find the current.

I = Q/t = 60/20 = 3 A
Answer: 3 A

Numerical 2 — Ohm’s Law

A resistor of 10 Ω is connected across a 20 V source.
Find the current.

I = V/R = 20/10 = 2 A
Answer: 2 A

Numerical 3 — Series Combination

Two resistors of 4 Ω and 6 Ω are connected in series.
Find their equivalent resistance.

R = R₁ + R₂ = 4 + 6 = 10 Ω
Answer: 10 Ω

Numerical 4 — Parallel Combination

Two resistors of 6 Ω and 3 Ω are connected in parallel.
Find their equivalent resistance.

1/R = 1/6 + 1/3 = 3/6 = 1/2

R = 2 Ω
Answer: 2 Ω

Numerical 5 — Electrical Power

A 100 Ω resistor is connected to a 200 V supply.
Find the electrical power consumed.

P = V²/R = (200)²/100 = 400 W
Answer: 400 W

Numerical 6 — Terminal Voltage

A cell has emf 12 V and internal resistance 1 Ω.
If it supplies 2 A current, find its terminal voltage.

V = ε − Ir = 12 − (2)(1) = 10 V
Answer: 10 V

High-Yield Current Electricity Concepts

Concept Remember Common Trap
Current I = Q/t Confusing current with charge
Drift velocity I = nAevd Ignoring cross-sectional area
Ohm’s law V = IR Assuming every material is ohmic
Resistance R = ρL/A Confusing R with ρ
Series Same current Using parallel formula
Parallel Same voltage Adding resistances directly
Cell delivering current V = ε − Ir Using the wrong sign
Junction rule ΣI = 0 Applying loop rule at a junction
Loop rule ΣΔV = 0 Ignoring sign convention
Power P = VI = I²R = V²/R Using the wrong form for given quantities

Common Mistakes in Current Electricity MCQs

  • Do not confuse resistance with resistivity.
  • Do not use series formulas for parallel circuits.
  • Remember that the same current flows through series elements.
  • Remember that the same potential difference exists across
    parallel branches.
  • For a discharging cell, terminal voltage is ε − Ir.
  • Always convert centimetres, millimetres and other units
    into SI units before numerical calculations.
  • Check whether a question gives power, voltage, current or
    resistance before selecting P = VI, I²R or V²/R.
  • In Kirchhoff problems, choose a consistent sign convention
    and follow it throughout the loop.

Exam Strategy — CBSE, NEET & JEE

CBSE Class 12

Focus on definitions, derivations, circuit reasoning,
graphs, Kirchhoff’s laws, cells, resistance combinations
and numerical applications.

NEET Physics

Prioritise rapid formula recognition, circuit combinations,
power, internal resistance, drift velocity and short
calculation-based MCQs.

JEE Main & Advanced

Go beyond direct substitution. Practise multi-resistor
networks, Kirchhoff equations, non-trivial combinations,
limiting cases and multi-step numerical reasoning.

Self-Assessment Challenge

Attempt the MCQs without looking at the answers first.
Then calculate your score.

  • 22–25:
    Excellent — exam-ready foundation
  • 18–21:
    Strong — revise weak concepts
  • 14–17:
    Developing — revisit formulas and circuit concepts
  • Below 14:
    Return to the Theory & Formula page and practise again

Next Step: Move from Practice to PYQs

Once you can consistently solve Current Electricity MCQs,
move to previous-year questions and exam-style problems.
PYQs reveal the way concepts are actually tested under exam
conditions.

Master Current Electricity Step by Step

Learn the theory → revise formulas → solve MCQs →
practise numericals → attack PYQs.


Current Electricity Master Hub


Theory & Formula Revision