Current Electricity — NEET Physics MCQs with answers

Current Electricity is a Class 12 Physics chapter in the NEET (UG) syllabus. NEET720 has 1,020 reviewed practice questions on it, each with a quick answer and a step-by-step explanation. The 8 questions below are free and fixed, so you can bookmark this page; the full chapter, plus mistake tracking and spaced revision, is in the app.

Topics covered

Electric current · Resistance and resistivity · Electric current and drift velocity · Ohm's law and resistivity · Resistor combinations and networks · Kirchhoff's laws · Cells, EMF and internal resistance · Electrical energy, power and heating · Wheatstone bridge and applications · Metre bridge (experimental skills) · Capacitor in DC circuits · Wheatstone Bridge / Meter Bridge · Resistors in combination · Electrical power and energy · Cells in combination · Kirchhoff's laws with Wheatstone bridge · EMF and internal resistance · Resistor networks · Drift velocity · Kirchhoff's loop rule · Potentiometer · Cells under charge and discharge · Electrical power · Current density · Drift velocity and resistivity temperature dependence · Resistivity and conductivity · Meter bridge · Ideal vs real voltmeter · Resistivity and temperature dependence · Ohm's law and non-ohmic devices · Resistors in series and parallel · Ohm's law misapplication · Wheatstone bridge sensitivity · EMF/internal resistance and power transfer · Potentiometer for cell comparison · Wheatstone bridge · Resistor combination · Combination of cells · Potentiometer for internal resistance · Electrical energy and power

8 free Current Electricity practice questions with answers

Choose an answer in your head before opening it. Each explanation says why the correct option is right and, where relevant, why the tempting wrong option is wrong.

1. Question 1 · easy · Cells, EMF and internal resistance

   The internal resistance of an electrolytic cell mainly depends on which of the following?

   • A.Only the value of the external resistor connected to it
   • B.Only the cell's EMF
   • C.The nature and concentration of the electrolyte, and the distance and common area of the electrodes immersed in it
   • D.Only the current flowing through the external circuit at a given instant
   Show answer and explanation

   Answer: C. The nature and concentration of the electrolyte, and the distance and common area of the electrodes immersed in it

   Internal resistance is an intrinsic property of the cell, set by the electrolyte's nature and concentration and by the geometry (spacing and immersed area) of its electrodes — not by whatever external resistor or current happens to be present.

   A cell's internal resistance arises from the resistance offered by the electrolyte and electrode surfaces to the flow of ions and charge inside the cell. It increases with greater electrode separation, decreases with greater common electrode area immersed in the electrolyte, and depends on the nature and concentration of the electrolyte used. It is an intrinsic property of the cell and does not depend on which external resistor is connected or on the instantaneous current (though internal resistance can drift with cell age, temperature, and depletion of the electrolyte over long use).

   Common mistake: Confusing internal resistance (intrinsic to the cell) with external circuit quantities such as R or I.

2. Question 2 · easy · Resistor combinations and networks

   In a series combination of several resistors connected across a battery, which physical quantity is the same through each resistor?

   • A.potential difference
   • B.power dissipated
   • C.current
   • D.none of these quantities is the same
   Show answer and explanation

   Answer: C. current

   In series, there is only one path for charge to flow, so the same current passes through every resistor.

   In a series circuit, resistors are connected end-to-end forming a single conducting path, so the same charge (and hence the same current) must flow through each one — by conservation of charge, current cannot pile up or vanish at any point in a single path. Voltage and power, however, generally differ across resistors of different resistance since V = IR and P = I²R.

   Common mistake: Confusing which quantity (current vs voltage) is common in series versus parallel circuits

3. Question 3 · easy · Resistor combinations and networks

   Several resistors are connected in parallel across a battery. Which physical quantity is the same across each resistor?

   • A.current
   • B.potential difference
   • C.power dissipated
   • D.none of these quantities is the same
   Show answer and explanation

   Answer: B. potential difference

   All resistors in a parallel combination share the same two nodes, so the potential difference across each is identical, even though currents and powers may differ.

   In a parallel combination, every resistor is connected between the same pair of junctions (nodes). Since potential is a single-valued property of a point in a circuit, the voltage across each resistor equals the potential difference between those two nodes — hence it is the same for every branch. Current, however, divides among branches according to I = V/R, so branches with smaller resistance carry more current; power (P = V²/R) likewise differs.

   Common mistake: Confusing which quantity (current vs voltage) is common in series versus parallel circuits

4. Question 4 · easy · Electric current and drift velocity

   In a metallic conductor connected to a battery, the conventional current flows from the positive terminal to the negative terminal through the external circuit. The free electrons inside the conductor actually drift:

   • A.from the negative terminal towards the positive terminal, i.e. opposite to the conventional current direction
   • B.in the same direction as the conventional current, since current is defined as the flow of charge
   • C.randomly, with no net direction, since only conventional current has a direction
   • D.perpendicular to the conventional current direction inside the wire
   Show answer and explanation

   Answer: A. from the negative terminal towards the positive terminal, i.e. opposite to the conventional current direction

   Conventional current direction is defined as the direction of positive charge flow. Since the actual charge carriers in a metal are negatively charged electrons, they drift opposite to the conventional current direction.

   By historical convention, current direction is taken as the direction in which positive charge would flow, i.e. from high to low potential through the external circuit (positive terminal to negative terminal). In a metallic conductor, the actual mobile charge carriers are free electrons, which are negatively charged. The electric field set up in the wire pushes electrons towards the positive terminal, i.e. opposite to the conventional current direction. Option B ignores the sign of the electron's charge; options C and D misdescribe drift direction entirely.

   Common mistake: Assuming electrons physically move in the same direction as the labelled conventional current

5. Question 5 · easy · Electric current and drift velocity

   A wire of non-uniform cross-section carries a steady current in a time-independent (DC) circuit. Compare the current through a narrow section P and a wider section Q of the same wire.

   • A.Current through P is greater than through Q, since P has smaller area
   • D.Current through P equals current through Q, by conservation of charge in a steady state
   • C.Current through Q is greater than through P, since Q has larger area
   • B.The comparison cannot be made without knowing the exact areas of P and Q
   Show answer and explanation

   Answer: D. Current through P equals current through Q, by conservation of charge in a steady state

   In steady-state DC flow through a single wire, charge cannot accumulate anywhere, so the same current must pass through every cross-section — narrow or wide.

   For a conductor carrying a steady (time-independent) current with no branching, conservation of charge requires that the charge entering any cross-section per second equals the charge leaving the next cross-section per second; otherwise charge would pile up somewhere, which cannot happen in steady state. Hence I_P = I_Q even though the wire's area changes. What does change between P and Q is the current density J = I/A (higher in the narrower section) and the drift velocity v_d = I/(nAe) (higher in the narrower section), but the current I itself stays the same.

   Common mistake: Confusing current density, which does vary with area, with current, which does not

6. Question 6 · easy · Kirchhoff's laws

   Kirchhoff's junction rule (current rule) at any node of a circuit is a direct consequence of which conservation principle?

   • A.Conservation of electric charge
   • B.Conservation of energy
   • C.Conservation of linear momentum
   • D.Conservation of magnetic flux
   Show answer and explanation

   Answer: A. Conservation of electric charge

   Since charge cannot accumulate at a junction in steady current flow, the total charge flowing in per second must equal the total charge flowing out per second — this is charge conservation.

   In steady-state DC circuits, no charge can pile up at a node (that would mean a changing charge density, contradicting steady flow). Hence the algebraic sum of currents entering a junction equals the sum leaving it: this is exactly a statement of local charge conservation. The loop rule, by contrast, is a statement of energy conservation (work done per unit charge around a closed path is zero). Momentum and flux conservation are unrelated to this rule.

   Common mistake: Mixing up which of Kirchhoff's two laws follows from charge conservation versus energy conservation.

7. Question 7 · medium · Kirchhoff's laws

   Kirchhoff's junction and loop rules remain valid even in a circuit containing a non-linear element such as a diode. This is because the two laws fundamentally rely on:

   • A.The assumption that all elements obey Ohm's law
   • B.The circuit being driven only by DC sources
   • C.All EMF sources in the circuit being identical
   • D.Conservation of charge and conservation of energy, which hold regardless of the nature of the circuit elements
   Show answer and explanation

   Answer: D. Conservation of charge and conservation of energy, which hold regardless of the nature of the circuit elements

   The junction rule follows from charge conservation and the loop rule from energy conservation — both hold universally, independent of whether elements are linear (resistors) or non-linear (diodes).

   Kirchhoff's rules are not derived from any particular current–voltage relationship of the circuit elements; they are consequences of two conservation laws that apply to any circuit: charge cannot accumulate at a node (junction rule), and the net work done per unit charge around any closed path is zero (loop rule). Since a diode, however non-linear its I–V characteristic, still obeys charge and energy conservation, both Kirchhoff rules apply to it exactly as they would to a resistor — only the relationship used to connect V and I within that one branch changes.

   Common mistake: Believing Kirchhoff's laws are tied to Ohm's law or to linear resistive elements.

8. Question 8 · medium · Kirchhoff's laws

   An ideal ammeter (in series, measuring branch current) and an ideal voltmeter (in parallel, measuring a voltage) are inserted into a circuit so that Kirchhoff's-law analysis of the original circuit is completely undisturbed. This requires the ammeter and voltmeter to have, respectively:

   • A.Very high resistance; very low resistance
   • B.Very high resistance; very high resistance
   • C.Very low resistance; very low resistance
   • D.Very low (ideally zero) resistance; very high (ideally infinite) resistance
   Show answer and explanation

   Answer: D. Very low (ideally zero) resistance; very high (ideally infinite) resistance

   An ideal ammeter must have zero resistance so it adds no extra IR drop to the branch it is placed in; an ideal voltmeter must have infinite resistance so it draws no current from the branch it is placed across.

   For Kirchhoff's-law equations written for the original circuit to remain valid after inserting meters, neither meter may alter the branch currents. A series ammeter with nonzero resistance would add an extra term to the loop equation for that branch, so it must be ideally zero. A parallel voltmeter with finite resistance would divert some current away from the branch (violating the junction rule as originally written), so it must be ideally infinite so that it draws negligible current.

   Common mistake: Confusing which meter needs zero resistance and which needs infinite resistance.

Questions about Current Electricity for NEET

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