Current Electricity MCQs 2026

The time constant of an RC charging circuit is given by

1. A R divided by C ✓
2. B C divided by R ✓
3. C RC ✓
4. D 1 divided by RC ✓

During charging of a capacitor through a resistor, the current in the circuit

1. A Decreases exponentially with time ✓
2. B Remains constant ✓
3. C Increases exponentially ✓
4. D Is zero throughout ✓

In the standard 4-band resistor color code, the third band represents the

1. A First significant digit ✓
2. B Multiplier ✓
3. C Tolerance ✓
4. D Second significant digit ✓

Faraday's first law of electrolysis states that the mass of substance deposited is proportional to

1. A The quantity of electric charge passed ✓
2. B The resistance of the electrolyte ✓
3. C The temperature of the electrolyte ✓
4. D The volume of the electrolyte ✓

A potential divider circuit is used to

1. A Increase voltage ✓
2. B Store energy ✓
3. C Obtain a variable voltage output from a fixed source ✓
4. D Measure current directly ✓

A rheostat is commonly used in a circuit to

1. A Measure current ✓
2. B Vary resistance and control current ✓
3. C Store charge ✓
4. D Measure voltage ✓

A material whose resistance decreases sharply with increase in temperature is called a

1. A Rheostat ✓
2. B Fuse ✓
3. C Conductor ✓
4. D Thermistor ✓

Earthing (grounding) in household wiring is provided mainly to

1. A Reduce electricity bills ✓
2. B Increase current flow ✓
3. C Protect users from electric shock due to leakage current ✓
4. D Improve bulb brightness ✓

Which of the following is generally a good conductor of electricity

1. A Copper ✓
2. B Rubber ✓
3. C Glass ✓
4. D Wood ✓

Current density is defined as

1. A Current per unit volume ✓
2. B Current per unit charge ✓
3. C Total charge per unit area ✓
4. D Current per unit cross-sectional area ✓

Drift velocity of electrons in a conductor refers to their

1. A Random thermal velocity ✓
2. B Average velocity gained due to an applied electric field ✓
3. C Speed of light in the conductor ✓
4. D Instantaneous velocity between collisions ✓

To convert a galvanometer into a voltmeter, a

1. A Low resistance is connected in parallel ✓
2. B Shunt is added in parallel ✓
3. C High resistance is connected in series ✓
4. D Low resistance is connected in series ✓

To convert a galvanometer into an ammeter, a

1. A Low resistance (shunt) is connected in parallel ✓
2. B High resistance is connected in series ✓
3. C High resistance is connected in parallel ✓
4. D Low resistance is connected in series ✓

A Wheatstone bridge is said to be balanced when

1. A Current flows through the galvanometer ✓
2. B All resistances are equal ✓
3. C The battery is disconnected ✓
4. D No current flows through the galvanometer ✓

The working principle of a potentiometer is based on

1. A Ohm's law only ✓
2. B Kirchhoff's laws ✓
3. C Comparison of potential differences using a uniform wire ✓
4. D Magnetic induction ✓

A material that offers zero resistance below a certain critical temperature is called a

1. A Superconductor ✓
2. B Semiconductor ✓
3. C Insulator ✓
4. D Thermistor ✓

When identical cells are connected in parallel, the equivalent EMF stays the same as one cell but the

1. A Voltage increases ✓
2. B Current-supplying capacity increases ✓
3. C Resistance increases ✓
4. D EMF doubles ✓

When cells are connected in series, the equivalent EMF is the

1. A Average of individual EMFs ✓
2. B Same as a single cell ✓
3. C Sum of individual EMFs ✓
4. D Difference of EMFs ✓

The terminal voltage of a cell is always in what relation to its EMF when the cell is discharging

1. A Greater than ✓
2. B Equal to ✓
3. C Independent of ✓
4. D Less than ✓

The electromotive force (EMF) of a cell is defined as the

1. A Potential difference across external resistance only ✓
2. B Energy supplied by the cell per unit charge ✓
3. C Current supplied by the cell ✓
4. D Internal resistance of the cell ✓

Joule's law of heating states that heat produced in a conductor is directly proportional to

1. A The square of current, resistance, and time ✓
2. B Current only ✓
3. C Resistance only ✓
4. D Time only ✓

The commercial unit of electrical energy is the

1. A Joule ✓
2. B Watt ✓
3. C Kilowatt-hour ✓
4. D Ampere-hour ✓

Electrical power dissipated in a resistor carrying current I with resistance R is given by

1. A P = V/I ✓
2. B P = I squared times R ✓
3. C P = R/I ✓
4. D P = V times A ✓

Kirchhoff's voltage law is based on the conservation of

1. A Charge ✓
2. B Momentum ✓
3. C Mass ✓
4. D Energy ✓

Kirchhoff's current law is based on the conservation of

1. A Electric charge ✓
2. B Energy ✓
3. C Momentum ✓
4. D Mass ✓

For resistors connected in parallel, the reciprocal of equivalent resistance equals

1. A Sum of resistances ✓
2. B Product of resistances ✓
3. C Sum of reciprocals of individual resistances ✓
4. D Average of resistances ✓

The equivalent resistance of resistors connected in series is

1. A Less than the smallest resistance ✓
2. B Reciprocal sum of individual resistances ✓
3. C Always equal for all resistors ✓
4. D Sum of individual resistances ✓

For most metallic conductors, resistance changes in what way with increase in temperature

1. A Increases ✓
2. B Decreases ✓
3. C Remains constant ✓
4. D Becomes zero ✓

Resistivity of a material depends on

1. A Length of the conductor ✓
2. B Nature of the material and temperature ✓
3. C Cross-sectional area only ✓
4. D Current flowing through it ✓

The resistance of a conductor is given by R = rho times L divided by A, where A represents

1. A Resistivity ✓
2. B Length ✓
3. C Cross-sectional area ✓
4. D Temperature coefficient ✓

Ohm's law states that current through a conductor is directly proportional to

1. A Potential difference across it, at constant temperature ✓
2. B Its resistance ✓
3. C Its length ✓
4. D Its cross-sectional area ✓

In conventional current flow, current is considered to flow from

1. A Negative to positive terminal externally ✓
2. B Electron flow direction ✓
3. C Low to high potential always ✓
4. D Positive terminal to negative terminal through the external circuit ✓

In household electrical wiring, a fuse is used to

1. A Increase voltage supply ✓
2. B Protect the circuit by breaking it during excess current flow ✓
3. C Store electrical energy ✓
4. D Convert AC to DC ✓

Which of the following is an example of a semiconductor

1. A Copper ✓
2. B Rubber ✓
3. C Silicon ✓
4. D Aluminium ✓

The SI unit of electromotive force (EMF) is the same as that of

1. A Potential difference (volt) ✓
2. B Current (ampere) ✓
3. C Resistance (ohm) ✓
4. D Charge (coulomb) ✓

A device used to measure electric current directly in a circuit is called an

1. A Voltmeter ✓
2. B Ammeter ✓
3. C Ohmmeter ✓
4. D Wattmeter ✓

A short circuit occurs when

1. A Resistance in a circuit becomes very high ✓
2. B Current stops flowing entirely ✓
3. C Voltage source is disconnected ✓
4. D Live and neutral wires touch directly, causing a very low resistance path ✓

Unlike DC, alternating current (AC)

1. A Flows only in one direction ✓
2. B Periodically reverses its direction ✓
3. C Cannot be measured ✓
4. D Has zero frequency ✓

The RMS value of an alternating current is the value that

1. A Produces the same heating effect as an equivalent direct current ✓
2. B Is always equal to the peak value ✓
3. C Is always zero ✓
4. D Is twice the peak value ✓

In a household electrical circuit, appliances are generally connected in

1. A Series, so all devices work with equal current ✓
2. B A single loop ✓
3. C Series-parallel randomly ✓
4. D Parallel, so each device gets full voltage independently ✓

In a series circuit, the current through each component is

1. A Different for each component ✓
2. B Dependent on resistance value ✓
3. C The same throughout the circuit ✓
4. D Zero at the battery terminals ✓

In a parallel circuit, the voltage across each branch is

1. A Divided among branches ✓
2. B The same as the source voltage ✓
3. C Zero ✓
4. D Dependent on current only ✓

Two resistors of 4 ohm and 6 ohm are connected in series. The equivalent resistance is

1. A 2.4 ohm ✓
2. B 24 ohm ✓
3. C 10 ohm ✓
4. D 1.5 ohm ✓

Two resistors of 6 ohm each are connected in parallel. The equivalent resistance is

1. A 3 ohm ✓
2. B 12 ohm ✓
3. C 6 ohm ✓
4. D 1.5 ohm ✓

Internal resistance of a cell is due to

1. A External circuit wires ✓
2. B The connecting wires' resistance ✓
3. C The ammeter used ✓
4. D Resistance offered by the electrolyte and electrodes inside the cell ✓

The unit of electrical resistivity is

1. A Ohm ✓
2. B Siemens ✓
3. C Ohm per metre ✓
4. D Ohm-metre ✓

The unit of electrical conductance is the

1. A Ohm ✓
2. B Siemens ✓
3. C Farad ✓
4. D Henry ✓

An ideal ammeter should have

1. A Very low (ideally zero) resistance ✓
2. B Very high resistance ✓
3. C Infinite resistance ✓
4. D Resistance equal to the circuit ✓

An ideal voltmeter should have

1. A Zero resistance ✓
2. B Low resistance ✓
3. C Resistance equal to load ✓
4. D Very high (ideally infinite) resistance ✓