Current & Electricity – 100 Higher-Order Thinking (HOTS) MCQs with Explanations | Competitive Exam Preparation

50 Higher-Order Thinking Skills (HOTS) MCQs (Level 3) on Current & Electricity, Physics (Unit-Wise MCQs Practice):

---

---

👉Physics MCQs Hub – Unit wise Physics MCQs Practice (Main-Page)👈

---

Whether you are preparing for board examinations, chapter tests, college assessments, or competitive entrance exams (MDCAT, ECAT, NUST, PIEAS, GIKI, UET, FAST, and other engineering or medical admission tests), this comprehensive MCQ collection is designed to help you master Current & Electricity. The questions are arranged progressively—from basic concepts to advanced numerical problems and higher-order thinking—ensuring complete and systematic preparation for every type of examination.

This chapter-wise MCQ collection includes:

• 100 Basic MCQs (1–100) – Covering steady current, drift velocity, Ohm's law, resistance, resistivity, conductivity, EMF, electric power, and related fundamental concepts.
• 100 Advanced & Numerical MCQs (101–200) – Focusing on calculations, circuit analysis, Kirchhoff's laws, Wheatstone bridge, potentiometer, thermistors, internal resistance, and power applications.
• 50 Higher-Order Thinking Skills (HOTS) MCQs (201–250) – Designed to develop conceptual understanding, analytical reasoning, and advanced problem-solving skills.
• 50 Challenging MCQs Quiz-1 with Answers (1–50) and 50 Challenging MCQs Quiz-2 with Answers (1–50) – A carefully selected mix of conceptual, numerical, and HOTS questions for quick revision, self-assessment, and complete exam preparation.

This MCQ collection covers:

• Steady current and drift velocity
• Ohm's law and electrical resistance
• Resistivity, conductivity, and conductance
• Temperature effects on resistance and resistivity
• Variable resistors, thermistors, and potential divider
• Electromotive force (EMF) and internal resistance
• Electric power and maximum power transfer
• Thermocouples and resistance thermometers
• Kirchhoff's Current Law (KCL) and Voltage Law (KVL)
• Wheatstone bridge and potentiometer

Every MCQ includes the correct answer with a clear, concept-based explanation to strengthen understanding, improve numerical ability, and reinforce key physics concepts.

This question bank helps students to:

• Build strong conceptual understanding
• Improve numerical and analytical skills
• Master electrical circuits and network analysis
• Strengthen problem-solving techniques
• Avoid common examination mistakes
• Increase speed, accuracy, and confidence
• Prepare effectively for both board and competitive examinations

With 250 carefully selected MCQs arranged into 100 Basic, 100 Advanced & Numerical, and 50 HOTS questions, along with 50 Challenging Quiz MCQs, this all-in-one Current & Electricity MCQ Bank provides complete preparation for examinations and competitive entrance tests while helping students achieve maximum scores.

---

Best Budget Laptops for Students for Study, Coding & Office Work 
(2026 Amazon Deals)

👉 Check Today’s Price on Amazon👈

👉 Check Acer Aspire 5 Price on Amazon

👉 Buy Lenovo IdeaPad Slim 3 on Amazon

👉 See HP Pavilion Latest Deal on Amazon

👉 View ASUS Vivobook 16 Details on Amazon

👉 Check MacBook Air Student Price on Amazon

---

Current & Electricity (Level 3) – 100 Higher-Order Thinking (HOTS) MCQs with Explanations (MCQs 201–300)

---

MCQ No. 201

A battery of emf 12 V and internal resistance 1 Ω is connected to an external resistor of 5 Ω. The terminal potential difference of the battery is:

a. 12 V
b. 10 V
c. 8 V
d. 6 V

Correct answer: b. 10 V

Explanation:
Current,

$$I=\frac{E}{R+r}=\frac{12}{5+1}=2\text{ A}$$

Terminal voltage,

$$V=E-Ir=12-(2\times1)=10\text{ V}$$

---

MCQ No. 202

A wire is stretched to three times its original length without changing its volume. Its new resistance becomes:

a. 3R
b. 6R
c. 9R
d. 12R

Correct answer: c. 9R

Explanation:
Since volume remains constant, area becomes one-third.

$$R\propto\frac{L}{A}=\frac{3L}{A/3}=9R$$

---

MCQ No. 203

A voltmeter is connected across the terminals of a cell. The reading decreases when the circuit is closed because:

a. emf decreases
b. internal resistance disappears
c. voltage is lost across internal resistance
d. current becomes zero

Correct answer: c. Voltage is lost across internal resistance.

Explanation:
When current flows, part of the emf is used across the internal resistance.

---

MCQ No. 204

A potentiometer is preferred over a voltmeter because it:

a. has low resistance
b. measures current directly
c. draws practically no current while measuring potential difference
d. is cheaper

Correct answer: c. Draws practically no current while measuring potential difference.

Explanation:
A potentiometer measures potential difference without loading the circuit.

---

MCQ No. 205

If the temperature of a metallic conductor increases while the applied voltage remains constant, the current through it will:

a. increase
b. remain constant
c. decrease
d. first increase then decrease

Correct answer: c. Decrease

Explanation:
Resistance of metals increases with temperature, so current decreases according to Ohm's law.

---

MCQ No. 206

The condition for maximum power transfer from a source to a load is:

a. Load resistance is zero
b. Load resistance is infinite
c. Load resistance equals internal resistance
d. Internal resistance is zero

Correct answer: c. Load resistance equals internal resistance.

Explanation:
According to the Maximum Power Transfer Theorem,

$$R=r$$

---

MCQ No. 207

A student connects an ammeter in parallel with a resistor. The most likely result is:

a. Correct current measurement
b. Ammeter may be damaged
c. Resistance increases
d. Circuit behaves normally

Correct answer: b. Ammeter may be damaged.

Explanation:
An ammeter has very low resistance and must always be connected in series.

---

MCQ No. 208

In a balanced Wheatstone bridge, no current flows through the galvanometer because:

a. resistance is infinite
b. potential difference across the galvanometer is zero
c. battery voltage becomes zero
d. galvanometer resistance is very high

Correct answer: b. Potential difference across the galvanometer is zero.

Explanation:
Equal potentials at both terminals prevent current from flowing.

---

MCQ No. 209

If two identical cells are connected in series, the equivalent emf becomes:

a. E/2
b. E
c. 2E
d. 4E

Correct answer: c. 2E

Explanation:
Series connection adds the emfs of identical cells.

---

MCQ No. 210

Which graph represents an ohmic conductor?

a. Curved I–V graph
b. Straight line through origin
c. Horizontal line
d. Vertical line

Correct answer: b. Straight line through origin

Explanation:
Ohm's law states that current is directly proportional to voltage.

---

MCQ No. 211

The SI unit of conductivity is equivalent to:

a. Ω m
b. Ω⁻¹ m⁻¹
c. Ω² m
d. Ω/m

Correct answer: b. Ω⁻¹ m⁻¹

Explanation:
Conductivity is the reciprocal of resistivity.

---

MCQ No. 212

When the diameter of a wire is doubled while keeping its length unchanged, its resistance becomes:

a. R/4
b. R/2
c. 2R
d. 4R

Correct answer: a. R/4

Explanation:
Area becomes four times larger, so resistance becomes one-fourth.

---

MCQ No. 213

Kirchhoff's Voltage Law is based on conservation of:

a. Mass
b. Charge
c. Energy
d. Momentum

Correct answer: c. Energy

Explanation:
The algebraic sum of potential differences around a closed loop is zero.

---

MCQ No. 214

Which material is most suitable for making standard resistors?

a. Copper
b. Aluminium
c. Manganin
d. Silver

Correct answer: c. Manganin

Explanation:
Manganin has very low temperature coefficient of resistance.

---

MCQ No. 215

If current through a resistor is doubled, the rate of heat production becomes:

a. Double
b. Four times
c. Half
d. Eight times

Correct answer: b. Four times

Explanation:
From Joule's law,

$$P=I^2R$$

---

MCQ No. 216

The drift velocity of electrons is directly proportional to:

a. Length of conductor
b. Electric field strength
c. Cross-sectional area only
d. Resistance only

Correct answer: b. Electric field strength

Explanation:
A stronger electric field produces a greater drift velocity.

---

MCQ No. 217

An ideal voltmeter should have:

a. Zero resistance
b. Infinite resistance
c. Low resistance
d. Moderate resistance

Correct answer: b. Infinite resistance

Explanation:
It should not draw any current from the circuit.

---

MCQ No. 218

A thermistor is mainly used for measuring:

a. Current
b. Temperature
c. Voltage
d. Resistance only

Correct answer: b. Temperature

Explanation:
Its resistance changes rapidly with temperature.

---

MCQ No. 219

Which quantity remains unchanged when a metallic wire is stretched?

a. Length
b. Area
c. Resistance
d. Resistivity

Correct answer: d. Resistivity

Explanation:
Resistivity depends only on the material and temperature.

---

MCQ No. 220

In a series circuit containing unequal resistors, the same quantity through each resistor is:

a. Voltage
b. Current
c. Power
d. Resistance

Correct answer: b. Current

Explanation:
Current remains the same throughout a series circuit.

---

MCQ No. 221

Which instrument is most suitable for comparing the emf of two cells accurately?

a. Ammeter
b. Voltmeter
c. Potentiometer
d. Galvanometer

Correct answer: c. Potentiometer

Explanation:
It compares emf without drawing current from the cells.

---

MCQ No. 222

The reciprocal of conductivity is:

a. Resistance
b. Resistivity
c. Conductance
d. Current density

Correct answer: b. Resistivity

Explanation:

$$\rho=\frac{1}{\sigma}$$

---

MCQ No. 223

A resistor has colour bands Brown–Black–Red. Its resistance is:

a. 10 Ω
b. 100 Ω
c. 1 kΩ
d. 10 kΩ

Correct answer: c. 1 kΩ

Explanation:
Brown = 1, Black = 0, Red = ×100.

$$10\times100=1000\,\Omega$$

---

MCQ No. 224

A fuse wire protects an electrical circuit because it has:

a. High melting point
b. Low melting point and relatively high resistance
c. High conductivity only
d. Zero resistance

Correct answer: b. Low melting point and relatively high resistance

Explanation:
It melts quickly during excessive current, protecting the circuit.

---

MCQ No. 225

The current through a conductor is 4 A for 5 minutes. The total charge transferred is:

a. 200 C
b. 600 C
c. 1200 C
d. 2400 C

Correct answer: c. 1200 C

Explanation:

$$Q=It=4\times300=1200\text{ C}$$

---

MCQ No. 226

A battery has an emf of 9 V and internal resistance of 0.5 Ω. When connected to a 4 Ω resistor, the efficiency of the battery is:

a. 80%
b. 88.9%
c. 90%
d. 95%

Correct answer: b. 88.9%

Explanation:
Efficiency,

$$\eta=\frac{R}{R+r}\times100 =\frac{4}{4+0.5}\times100 =88.9\%$$

---

MCQ No. 227

Two wires are made of the same material. One has twice the length and twice the diameter of the other. Their resistances are in the ratio:

a. 1 : 1
b. 1 : 2
c. 2 : 1
d. 4 : 1

Correct answer: b. 1 : 2

Explanation:

$$R\propto\frac{L}{A}$$

Length doubles while area becomes four times, so

$$R'=\frac{2}{4}R=\frac{R}{2}$$

---

MCQ No. 228

A potentiometer is more accurate than a voltmeter because it:

a. has lower resistance

b. measures resistance directly

c. works on the null-deflection principle

d. consumes more current

Correct answer: c. Works on the null-deflection principle

Explanation:
At balance point, no current is drawn from the source being measured.

---

MCQ No. 229

A current of 3 A flows through a resistor for 10 minutes. If the resistance is 20 Ω, the heat produced is:

a. 18 kJ

b. 54 kJ

c. 108 kJ

d. 216 kJ

Correct answer: c. 108 kJ

Explanation:

$$H=I^2Rt =3^2\times20\times600 =108000\text{ J}=108\text{ kJ}$$

---

MCQ No. 230

The resistance of a conductor increases by 0.4% per °C. If its resistance at 20°C is 50 Ω, its resistance at 70°C is approximately:

a. 55 Ω

b. 60 Ω

c. 65 Ω

d. 70 Ω

Correct answer: b. 60 Ω

Explanation:

$$R=R_0(1+\alpha\Delta T)$$
$$R=50(1+0.004\times50)=60\Omega$$

---

MCQ No. 231

A galvanometer is converted into an ammeter by connecting:

a. high resistance in series

b. low resistance in series

c. low resistance in parallel

d. high resistance in parallel

Correct answer: c. Low resistance in parallel

Explanation:
A shunt resistance allows most of the current to bypass the galvanometer.

---

MCQ No. 232

In a balanced Wheatstone bridge, if one resistance is doubled, the bridge can again be balanced by:

a. doubling the adjacent arm

b. doubling the opposite arm

c. halving the corresponding ratio arm

d. increasing battery voltage

Correct answer: c. Halving the corresponding ratio arm

Explanation:
Balance condition:

$$\frac{P}{Q}=\frac{R}{S}$$

---

MCQ No. 233

A resistor is connected across a cell. If the internal resistance becomes zero, then:

a. current decreases

b. terminal voltage decreases

c. terminal voltage becomes equal to emf

d. power becomes zero

Correct answer: c. Terminal voltage becomes equal to emf

Explanation:
With zero internal resistance,

$$V=E$$

---

MCQ No. 234

Current density in a conductor depends directly upon:

a. drift velocity

b. resistivity

c. resistance

d. potential only

Correct answer: a. Drift velocity

Explanation:

$$J=neV_d$$

---

MCQ No. 235

The colour bands Red–Violet–Orange represent a resistance of:

a. 2.7 kΩ

b. 27 Ω

c. 270 Ω

d. 27 kΩ

Correct answer: a. 2.7 kΩ

Explanation:
Red = 2, Violet = 7, Orange = ×100

$$27\times100=2700\Omega=2.7k\Omega$$

---

MCQ No. 236

If the electric field inside a conductor becomes zero, the drift velocity of free electrons becomes:

a. maximum

b. constant

c. zero

d. infinite

Correct answer: c. Zero

Explanation:
Without an electric field, there is no net drift of electrons.

---

MCQ No. 237

Two identical cells are connected in parallel. The equivalent emf is:

a. E/2

b. E

c. 2E

d. 4E

Correct answer: b. E

Explanation:
Parallel connection keeps emf unchanged while reducing internal resistance.

---

MCQ No. 238

A wire is stretched uniformly until its resistance becomes sixteen times. Its length becomes:

a. Twice

b. Three times

c. Four times

d. Sixteen times

Correct answer: a. Twice

Explanation:
Since

$$R\propto L^2$$

(for constant volume),

$$16=\left(\frac{L'}{L}\right)^2$$

Hence,

$$L'=4L$$

---

MCQ No. 239

The main advantage of manganin wire in electrical instruments is its:

a. high resistivity and low temperature coefficient

b. low resistivity

c. high conductivity

d. high melting point only

Correct answer: a. High resistivity and low temperature coefficient

Explanation:
Its resistance remains nearly constant with temperature.

---

MCQ No. 240

Which statement about electric current is correct?

a. Electrons move from high to low potential.

b. Conventional current flows from low to high potential.

c. Conventional current flows from high to low potential.

d. Both electrons and conventional current move in the same direction.

Correct answer: c. Conventional current flows from high to low potential.

Explanation:
Conventional current is opposite to the direction of electron flow.

---

MCQ No. 241

The power dissipated in a resistor connected to a constant voltage source is directly proportional to:

a. Resistance

b. Current

c. Reciprocal of resistance

d. Resistivity

Correct answer: c. Reciprocal of resistance

Explanation:

$$P=\frac{V^2}{R}$$

---

MCQ No. 242

The balance point in a potentiometer shifts towards the positive end when:

a. emf being measured increases

b. potentiometer current increases

c. wire length decreases

d. resistance becomes zero

Correct answer: a. emf being measured increases

Explanation:
Greater emf requires a longer balancing length.

---

MCQ No. 243

A conductor obeys Ohm's law only when:

a. temperature remains constant

b. voltage is zero

c. current is zero

d. resistance changes continuously

Correct answer: a. Temperature remains constant

Explanation:
Ohm's law is valid only if physical conditions remain unchanged.

---

MCQ No. 244

A thermocouple works on the principle of:

a. Joule heating

b. Seebeck effect

c. Hall effect

d. Photoelectric effect

Correct answer: b. Seebeck effect

Explanation:
A temperature difference between two junctions produces an emf.

---

MCQ No. 245

The internal resistance of a cell can be determined accurately using a:

a. Voltmeter

b. Ammeter

c. Potentiometer

d. Galvanometer

Correct answer: c. Potentiometer

Explanation:
A potentiometer measures emf and terminal voltage accurately, allowing calculation of internal resistance.

---

MCQ No. 246

For a fixed potential difference, doubling the resistance causes the electric power to become:

a. Double

b. Half

c. Four times

d. One-fourth

Correct answer: b. Half

Explanation:

$$P=\frac{V^2}{R}$$

---

MCQ No. 247

Which quantity is conserved at every junction in an electrical circuit?

a. Energy

b. Charge

c. Momentum

d. Voltage

Correct answer: b. Charge

Explanation:
Kirchhoff's Current Law is based on conservation of charge.

---

MCQ No. 248

The electrical conductivity of metals generally:

a. increases with temperature

b. decreases with temperature

c. remains constant

d. becomes zero

Correct answer: b. Decreases with temperature

Explanation:
As temperature rises, collisions increase and conductivity decreases.

---

MCQ No. 249

A resistance thermometer measures temperature by observing changes in:

a. current

b. resistance

c. capacitance

d. inductance

Correct answer: b. Resistance

Explanation:
The resistance of the sensing element changes predictably with temperature.

---

MCQ No. 250

Two identical resistors are connected first in series and then in parallel across the same battery. The ratio of powers consumed is:

a. 1 : 4

b. 4 : 1

c. 2 : 1

d. 1 : 2

Correct answer: a. 1 : 4

Explanation:
For identical resistors,

$$R_s=2R,\qquad R_p=\frac{R}{2}$$

Since

$$P=\frac{V^2}{R},$$
$$P_s:P_p=\frac{V^2}{2R}:\frac{2V^2}{R}=1:4.$$

---

MCQ No. 251

A 12 V battery with an internal resistance of 1 Ω supplies current to an external resistance of 3 Ω. The power delivered to the external resistor is:

a. 18 W
b. 27 W
c. 36 W
d. 48 W

Correct answer: b. 27 W

Explanation:
Current,

$$I=\frac{12}{3+1}=3\text{ A}$$

Power in external resistor,

$$P=I^2R=3^2\times3=27\text{ W}$$

---

MCQ No. 252

A student wants to measure the emf of a cell accurately. Which instrument should be preferred?

a. Ammeter
b. Voltmeter
c. Potentiometer
d. Galvanometer

Correct answer: c. Potentiometer

Explanation:
A potentiometer measures emf without drawing current from the cell, giving more accurate results.

---

MCQ No. 253

Two resistors of 6 Ω and 3 Ω are connected in parallel. Their equivalent resistance is:

a. 1 Ω
b. 2 Ω
c. 4 Ω
d. 9 Ω

Correct answer: b. 2 Ω

Explanation:

$$\frac{1}{R}=\frac{1}{6}+\frac{1}{3}=\frac{3}{6}$$
$$R=2\Omega$$

---

MCQ No. 254

The drift velocity of electrons in a conductor becomes zero when:

a. Resistance becomes zero

b. Electric field becomes zero

c. Temperature becomes zero

d. Current becomes maximum

Correct answer: b. Electric field becomes zero

Explanation:
Drift velocity exists only when an electric field is applied.

---

MCQ No. 255

The resistance of a conductor changes from 10 Ω to 12 Ω when its temperature rises by 50°C. Its temperature coefficient is approximately:

a. 0.002 °C⁻¹

b. 0.004 °C⁻¹

c. 0.006 °C⁻¹

d. 0.008 °C⁻¹

Correct answer: b. 0.004 °C⁻¹

Explanation:

\alpha=\frac{\Delta R}{R_0\Delta T} =\frac{2}{10\times50}=0.004\;^\circ C^{-1}

---

MCQ No. 256

Kirchhoff's Current Law is a direct consequence of the conservation of:

a. Energy

b. Momentum

c. Charge

d. Mass

Correct answer: c. Charge

Explanation:
The total current entering a junction equals the total current leaving it.

---

MCQ No. 257

The resistance of a metallic wire becomes one-fourth if its diameter is:

a. Doubled

b. Halved

c. Quadrupled

d. Unchanged

Correct answer: a. Doubled

Explanation:
Area becomes four times, therefore resistance becomes one-fourth.

---

MCQ No. 258

An ideal source of emf should have:

a. Infinite internal resistance

b. Zero internal resistance

c. High resistance

d. Variable resistance

Correct answer: b. Zero internal resistance

Explanation:
No energy is lost inside an ideal source.

---

MCQ No. 259

The Wheatstone bridge is most sensitive when:

a. All four resistances are nearly equal

b. One resistance is very large

c. One resistance is zero

d. Battery voltage is maximum

Correct answer: a. All four resistances are nearly equal

Explanation:
Sensitivity is maximum when the bridge arms have nearly equal resistances.

---

MCQ No. 260

The slope of an I–V graph for an ohmic conductor represents:

a. Resistance

b. Conductance

c. Resistivity

d. Current density

Correct answer: b. Conductance

Explanation:
Slope

$$=\frac{I}{V}=\frac{1}{R}$$

which is conductance.

---

MCQ No. 261

A resistor dissipates 100 W at 10 A. Its resistance is:

a. 0.1 Ω

b. 1 Ω

c. 10 Ω

d. 100 Ω

Correct answer: b. 1 Ω

Explanation:

$$P=I^2R$$
$$R=\frac{100}{10^2}=1\Omega$$

---

MCQ No. 262

Which device converts thermal energy directly into electrical energy?

a. Thermistor

b. Thermocouple

c. Rheostat

d. Potentiometer

Correct answer: b. Thermocouple

Explanation:
A thermocouple works on the Seebeck effect.

---

MCQ No. 263

The current through a resistor is doubled while its resistance is halved. The power becomes:

a. Same

b. Twice

c. Four times

d. Eight times

Correct answer: d. Eight times

Explanation:

$$P=I^2R$$

New power

$$=(2I)^2\times\frac{R}{2}=8P$$

---

MCQ No. 264

The SI unit of conductance is:

a. Ohm

b. Siemens

c. Ohm-meter

d. Mho-meter

Correct answer: b. Siemens

Explanation:
Conductance is measured in siemens (S).

---

MCQ No. 265

The balancing length of a potentiometer depends upon:

a. emf being measured

b. Diameter of the wire

c. Resistance of galvanometer only

d. Shape of the battery

Correct answer: a. emf being measured

Explanation:
Greater emf requires a greater balancing length.

---

MCQ No. 266

A resistor with colour bands Brown–Black–Orange has a value of:

a. 100 Ω

b. 1 kΩ

c. 10 kΩ

d. 100 kΩ

Correct answer: c. 10 kΩ

Explanation:
Brown = 1, Black = 0, Orange = ×1000

$$10\times1000=10000\Omega$$

---

MCQ No. 267

Which material has the highest electrical conductivity?

a. Copper

b. Iron

c. Silver

d. Aluminium

Correct answer: c. Silver

Explanation:
Silver possesses the highest electrical conductivity among common metals.

---

MCQ No. 268

Current density depends on:

a. Cross-sectional area only

b. Current only

c. Current per unit area

d. Length of conductor

Correct answer: c. Current per unit area

Explanation:

$$J=\frac{I}{A}$$

---

MCQ No. 269

A voltmeter should always be connected:

a. In series

b. In parallel

c. In series-parallel

d. Across the battery only

Correct answer: b. In parallel

Explanation:
A voltmeter measures the potential difference across a component.

---

MCQ No. 270

A battery of emf 6 V delivers 2 A through an external resistance of 2 Ω. The internal resistance is:

a. 0.5 Ω

b. 1 Ω

c. 2 Ω

d. 3 Ω

Correct answer: b. 1 Ω

Explanation:

$$E=I(R+r)$$
$$6=2(2+r)$$
$$r=1\Omega$$

---

MCQ No. 271

The electrical resistance of a conductor is minimum when:

a. Temperature is high

b. Length is maximum

c. Cross-sectional area is maximum

d. Resistivity is high

Correct answer: c. Cross-sectional area is maximum

Explanation:

$$R=\frac{\rho L}{A}$$

---

MCQ No. 272

In a series circuit, if one resistor burns out, the current through the remaining resistors:

a. Increases

b. Decreases slightly

c. Becomes zero

d. Remains unchanged

Correct answer: c. Becomes zero

Explanation:
An open circuit stops current throughout the series circuit.

---

MCQ No. 273

The reciprocal of resistivity is called:

a. Resistance

b. Conductivity

c. Conductance

d. Mobility

Correct answer: b. Conductivity

Explanation:

$$\sigma=\frac{1}{\rho}$$

---

MCQ No. 274

A conductor carrying current remains electrically neutral because:

a. Electrons disappear

b. Positive ions move with electrons

c. Equal amounts of positive and negative charges exist

d. No charge flows

Correct answer: c. Equal amounts of positive and negative charges exist.

Explanation:
Although electrons move, the conductor remains overall electrically neutral.

---

MCQ No. 275

A rheostat is mainly used to:

a. Increase emf

b. Store electrical energy

c. Vary current in a circuit

d. Measure resistance

Correct answer: c. Vary current in a circuit

Explanation:
A rheostat is a variable resistor used to control the current flowing through a circuit.

---

MCQ No. 276

A cell has an emf of 2.0 V and an internal resistance of 0.5 Ω. It is connected to an external resistance of 3.5 Ω. The current in the circuit is:

a. 0.25 A
b. 0.40 A
c. 0.50 A
d. 1.00 A

Correct answer: c. 0.50 A

Explanation:
Total resistance:

$$R_{\text{total}}=3.5+0.5=4\,\Omega$$

Current:

$$I=\frac{E}{R+r}=\frac{2}{4}=0.5\text{ A}$$

---

MCQ No. 277

If the diameter of a wire is reduced to one-half while its length remains unchanged, its resistance becomes:

a. Half

b. Double

c. Four times

d. Eight times

Correct answer: c. Four times

Explanation:
Since

$$A\propto d^2$$

halving the diameter reduces the area to one-fourth, so resistance becomes four times.

---

MCQ No. 278

The balancing length of a potentiometer decreases when:

a. Potential gradient increases

b. Potential gradient decreases

c. EMF increases

d. Length of wire increases

Correct answer: a. Potential gradient increases

Explanation:
Since

$$E=kL$$

for the same emf, increasing the potential gradient reduces the balancing length.

---

MCQ No. 279

A resistor and a thermistor are connected in series. As temperature increases, the current through the circuit generally:

a. Always increases

b. Always decreases

c. Depends on the characteristics of the thermistor

d. Remains constant

Correct answer: c. Depends on the characteristics of the thermistor

Explanation:
The overall resistance depends on whether the thermistor has a positive or negative temperature coefficient.

---

MCQ No. 280

Which statement correctly explains why copper is widely used for electrical wiring?

a. It has high resistance.

b. It has high resistivity.

c. It has low resistivity and high conductivity.

d. It has a high temperature coefficient only.

Correct answer: c. It has low resistivity and high conductivity.

Explanation:
Copper offers very little opposition to current, making it suitable for electrical wiring.

---

MCQ No. 281

In a circuit, two identical cells are connected in opposition. The net emf is:

a. E

b. 2E

c. E/2

d. Zero

Correct answer: d. Zero

Explanation:
Equal emfs connected in opposite directions cancel each other.

---

MCQ No. 282

Which of the following quantities remains unchanged when identical resistors are connected in parallel?

a. Equivalent resistance

b. Current through each resistor

c. Potential difference across each resistor

d. Total current

Correct answer: c. Potential difference across each resistor.

Explanation:
In a parallel circuit, every branch has the same potential difference.

---

MCQ No. 283

A conductor carries a current of 4 A for 15 minutes. The total charge passing through it is:

a. 900 C

b. 1800 C

c. 3600 C

d. 5400 C

Correct answer: c. 3600 C

Explanation:

$$Q=It$$
$$Q=4\times900=3600\text{ C}$$

---

MCQ No. 284

Which instrument is based on the null method of measurement?

a. Ammeter

b. Voltmeter

c. Potentiometer

d. Galvanometer

Correct answer: c. Potentiometer

Explanation:
A potentiometer gives accurate measurements by balancing voltages without drawing current.

---

MCQ No. 285

The power dissipated in a resistor connected to a constant current source is proportional to:

a. $R^2$

b. $1/R$

c. R

d. $\sqrt{R}$

Correct answer: c. R

Explanation:
For constant current,

$$P=I^2R$$

---

MCQ No. 286

A carbon resistor has colour bands Yellow–Violet–Brown. Its resistance is:

a. 470 Ω

b. 4700 Ω

c. 47 Ω

d. 4.7 Ω

Correct answer: a. 470 Ω

Explanation:
Yellow = 4

Violet = 7

Brown = ×10

$$47\times10=470\,\Omega$$

---

MCQ No. 287

Current density is greatest in the conductor having:

a. Largest cross-sectional area

b. Lowest current

c. Highest current per unit area

d. Greatest length

Correct answer: c. Highest current per unit area

Explanation:

$$J=\frac{I}{A}$$

---

MCQ No. 288

A battery delivers maximum power to an external resistor when:

a. External resistance is zero

b. External resistance equals internal resistance

c. External resistance is infinite

d. Internal resistance is zero

Correct answer: b. External resistance equals internal resistance.

Explanation:
This is the condition for maximum power transfer.

---

MCQ No. 289

If the current through a conductor becomes three times while resistance remains constant, the heat produced in the same time becomes:

a. Three times

b. Six times

c. Nine times

d. Twelve times

Correct answer: c. Nine times

Explanation:
From Joule's law,

$$H=I^2Rt$$

Heat varies as the square of current.

---

MCQ No. 290

The SI unit of resistivity is:

a. Ω

b. Ω m

c. S

d. S m⁻¹

Correct answer: b. Ω m

Explanation:
Resistivity is measured in ohm metre (Ω m).

---

MCQ No. 291

A voltmeter should ideally have:

a. Very low resistance

b. Infinite resistance

c. Zero resistance

d. Variable resistance

Correct answer: b. Infinite resistance

Explanation:
It draws negligible current and does not disturb the circuit.

---

MCQ No. 292

The conductivity of a metallic conductor generally decreases with increasing temperature because:

a. Number of free electrons decreases rapidly

b. Atomic vibrations increase, causing more collisions

c. Mass of electrons increases

d. Electron charge decreases

Correct answer: b. Atomic vibrations increase, causing more collisions.

Explanation:
More frequent collisions reduce electron mobility.

---

MCQ No. 293

A Wheatstone bridge is balanced when:

a. Current through the battery is zero

b. Potential difference across the galvanometer is zero

c. All four resistances are equal

d. External resistance is maximum

Correct answer: b. Potential difference across the galvanometer is zero.

Explanation:
No current flows through the galvanometer at balance.

---

MCQ No. 294

A wire has resistance R. If both its length and diameter are doubled, its new resistance becomes:

a. R

b. R/2

c. R/4

d. 2R

Correct answer: b. R/2

Explanation:
Area becomes four times.

$$R'=\rho\frac{2L}{4A}=\frac{R}{2}$$

---

MCQ No. 295

A thermocouple converts:

a. Chemical energy into electrical energy

b. Mechanical energy into electrical energy

c. Thermal energy into electrical energy

d. Electrical energy into heat

Correct answer: c. Thermal energy into electrical energy

Explanation:
It operates on the Seebeck effect.

---

MCQ No. 296

The current through a conductor is directly proportional to:

a. Resistance

b. Resistivity

c. Potential difference (at constant temperature)

d. Length

Correct answer: c. Potential difference (at constant temperature)

Explanation:
This is Ohm's law.

---

MCQ No. 297

The reciprocal of resistance is called:

a. Conductivity

b. Conductance

c. Resistivity

d. Current density

Correct answer: b. Conductance

Explanation:

$$G=\frac{1}{R}$$

---

MCQ No. 298

An electric eel can produce a high voltage primarily for:

a. Lighting

b. Communication

c. Hunting prey and self-defense

d. Producing heat

Correct answer: c. Hunting prey and self-defense

Explanation:
The electric discharge is used to stun prey and protect against predators.

---

MCQ No. 299

Which law is applied to determine unknown currents in complex electrical networks?

a. Coulomb's law

b. Faraday's law

c. Kirchhoff's laws

d. Gauss's law

Correct answer: c. Kirchhoff's laws

Explanation:
Kirchhoff's Current Law and Voltage Law are used for solving complex circuits.

---

MCQ No. 300

A resistor is connected across a constant voltage source. If its resistance is reduced to one-third of its original value, the power consumed becomes:

a. One-third

b. Three times

c. Six times

d. Nine times

Correct answer: b. Three times

Explanation:
For constant voltage,

$$P=\frac{V^2}{R}$$

If resistance becomes

$$\frac{R}{3},$$

then

$$P'=\frac{V^2}{R/3}=3P.$$

---

📚 Continue Your Physics Preparation

If you found this quiz helpful, explore our complete collection of Physics learning resources.

🔬 Physics MCQs Hub

---

More Study Resources for Students and Teachers

• Computer Science 11th Class Notes (Main Page) 
• Computer Science 12th Class Notes (Main Page) 

************************************

1. English Poems Analysis Hub– A to Z Index (English Poetry) 

(https://poemanalysishub.blogspot.com/p/english-poems-analysis-to-z-index.html)

2. Website for School and College Level Mathematics  

(https://askraremaths.blogspot.com)

3. ASK Rare Class Notes – Study Resources for Students & Teachers 

(https://askrareclassnotes.blogspot.com/)

© 2026 & onwards Academic Skills and Knowledge (ASK)   

Note:  Write me in the comments box below for any query and also Share this information with your classmates and friends.

---

© https://askrareclassnotes.blogspot.com | Learn • Practice • Succeed

---

Best Tools and Supplies for Students and Teachers:

📚 Grammar Books – Improve Writing, Score Higher
🪑 Study Chairs – Sit Comfortably, Study Better
🛋️ Study Desks – Organized Space, Better Learning
💡 Desk Lamps – Bright Light, Better Focus
⌚ Digital Watches– Manage Time, Improve Results
📱 Phone Stands – Hands-Free Learning Made Easy
🎧 Headphones – Focus Better, Learn Without Distractions
⌨️ Wireless Keyboards – Type Faster, Work Smarter
🖱️ Wireless Mouse – Smooth Control, Better Workflow
🖨️ Printers – Print Smart, Save Time

Disclosure: The above links on this page are affiliate links. This means that if you make a purchase through them, I may earn a small commission at no additional cost to you. Your support helps me maintain, improve, and continue providing valuable free content on this website.

With Best Regards

ASKRare Team

---

---

🌍📖

"Knowledge grows when it is shared."

At ASK Rare Class Notes, we believe quality education should be freely accessible to everyone. Learn, share, inspire, and help others succeed.