100 Important MCQs (Set-1 of Basic to Moderate MCQs) on Current & Electricity, Physics (Unit-Wise MCQs Practice):
This post contains carefully selected Multiple-Choice Questions (MCQs) (Set-1 from Basic to Moderate Level) from Current & Electricity of Physics, prepared strictly according to the latest board exam syllabus. These MCQs include a balanced combination of conceptual understanding and numerical problem-solving, making them revision-friendly, exam-oriented, and high-scoring.
Whether you are preparing for annual board examinations, chapter tests, or competitive entry tests, this comprehensive MCQ collection thoroughly covers the fundamental principles of Current & Electricity—starting from Steady Current and Ohm’s Law to Kirchhoff’s Laws and Potentiometers—helping students build strong conceptual clarity and numerical confidence.
This unit-wise MCQ set includes questions from:
• Steady Current and Drift Velocity in Conductors
• Ohm’s Law and its applications
• Electrical Resistance and Factors affecting Resistance
• Specific Resistance or Resistivity, Conductance, and Conductivity
• Effect of Temperature on Resistance and Temperature Coefficient of Resistance
• EMF of Cells, Internal Resistance, and Terminal Voltage
• Electric Power, Maximum Power Transfer, and Energy Dissipation
• Thermocouples, Thermistors, and Resistance Thermometers
• Kirchhoff’s Current Law (KCL) and Voltage Law (KVL)
• Wheatstone Bridge and Potentiometer – theory and numerical applications
Each MCQ is provided with the correct answer and a clear, concise explanation, helping students to:
- Strengthen conceptual understanding of current, voltage, and resistance phenomena
- Avoid common mistakes in numerical problems involving Ohm’s law, EMF, and resistivity
- Improve problem-solving skills for series-parallel circuits, bridges, and potentiometer setups
- Master practical applications of Kirchhoff’s Laws and maximum power transfer
- Achieve maximum marks in the MCQ section
This all-in-one Current & Electricity MCQ collection is an essential revision tool for all students aiming to excel in Physics exams and fully master the concepts of current, resistance, EMF, power, thermoelectric effects, and circuit analysis.
MCQ No. 1
Electric current is defined as:
a. Flow of energy per second
b. Flow of charge per unit time
c. Force per unit charge
d. Work done per unit charge
Correct answer: b. Flow of charge per unit time
Explanation:
Current I = Q/t, where Q is charge and t is time.
MCQ No. 2
SI unit of electric current is:
a. Volt
b. Coulomb
c. Ampere
d. Ohm
Correct answer: c. Ampere
Explanation:
Ampere is the SI unit of electric current.
MCQ No. 3
Which particles carry current in metallic conductors?
a. Protons
b. Positive ions
c. Neutrons
d. Electrons
Correct answer: d. Electrons
Explanation:
Free electrons are responsible for conduction in metals.
MCQ No. 4
Drift velocity of electrons is of the order of:
a. 10⁶ m/s
b. 10² m/s
c. 10⁻³ m/s
d. 1 m/s
Correct answer: c. 10⁻³ m/s
Explanation:
Electron drift speed is very small, about 10⁻³ m/s.
MCQ No. 5
Ohm’s law is represented by:
a. V = IR
b. I = VR
c. R = VI
d. V = I/R
Correct answer: a. V = IR
Explanation:
Ohm’s law states that voltage is proportional to current.
MCQ No. 6
Resistance of a conductor depends on:
a. Length only
b. Area only
c. Material only
d. Length, area, and material
Correct answer: d. Length, area, and material
Explanation:
R = ρL/A shows dependence on length, area, and material.
MCQ No. 7
SI unit of resistance is:
a. Ampere
b. Volt
c. Ohm
d. Coulomb
Correct answer: c. Ohm
Explanation:
Resistance is measured in ohms (Ω).
MCQ No. 8
If voltage is doubled and resistance remains constant, current becomes:
a. Half
b. Same
c. Double
d. Four times
Correct answer: c. Double
Explanation:
From I = V/R, doubling V doubles I.
MCQ No. 9
Which graph represents an ohmic conductor?
a. Curve
b. Circle
c. Straight line
d. Parabola
Correct answer: c. Straight line
Explanation:
Ohmic conductors obey V ∝ I, giving straight-line graph.
MCQ No. 10
Unit of resistivity is:
a. Ω
b. Ω m
c. Ω/m
d. m/Ω
Correct answer: b. Ω m
Explanation:
Resistivity unit is ohm–meter.
MCQ No. 11
Conductance is reciprocal of:
a. Resistivity
b. Resistance
c. Current
d. Voltage
Correct answer: b. Resistance
Explanation:
G = 1/R.
MCQ No. 12
SI unit of conductance is:
a. Ohm
b. Volt
c. Siemens
d. Coulomb
Correct answer: c. Siemens
Explanation:
Conductance is measured in Siemens (S).
MCQ No. 13
Current in an open circuit is:
a. Maximum
b. Minimum
c. Zero
d. Infinite
Correct answer: c. Zero
Explanation:
No closed path → no current.
MCQ No. 14
Which quantity remains same in series circuit?
a. Voltage
b. Power
c. Resistance
d. Current
Correct answer: d. Current
Explanation:
Same current flows through all series components.
MCQ No. 15
Which quantity remains same in parallel circuit?
a. Current
b. Voltage
c. Resistance
d. Power
Correct answer: b. Voltage
Explanation:
Each branch has same potential difference.
MCQ No. 16
EMF of a cell is defined as:
a. Terminal voltage
b. Energy supplied per unit charge
c. Current per unit resistance
d. Force on electrons
Correct answer: b. Energy supplied per unit charge
Explanation:
EMF = work done per coulomb.
MCQ No. 17
Internal resistance of ideal cell is:
a. Infinite
b. Zero
c. One ohm
d. Very large
Correct answer: b. Zero
Explanation:
Ideal cell has no internal resistance.
MCQ No. 18
If length of wire is doubled, resistance becomes:
a. Half
b. Same
c. Double
d. Four times
Correct answer: c. Double
Explanation:
R ∝ L.
MCQ No. 19
A fuse wire has:
a. High melting point
b. Low melting point
c. Zero resistance
d. High density
Correct answer: b. Low melting point
Explanation:
Fuse melts quickly to protect circuit.
MCQ No. 20
Terminal voltage of a cell in open circuit equals:
a. Zero
b. EMF
c. Half EMF
d. Double EMF
Correct answer: b. EMF
Explanation:
No current → no internal drop.
MCQ No. 21
Power in electric circuit is:
a. VI
b. V/I
c. IR
d. R/I
Correct answer: a. VI
Explanation:
Electrical power P = VI.
MCQ No. 22
Unit of electric power is:
a. Joule
b. Watt
c. Volt
d. Ampere
Correct answer: b. Watt
Explanation:
Power is measured in watts.
MCQ No. 23
Drift velocity increases when:
a. Temperature increases
b. Area increases
c. Voltage increases
d. Length increases
Correct answer: c. Voltage increases
Explanation:
Higher electric field increases drift velocity.
MCQ No. 24
Charge flowing per second is:
a. Voltage
b. Power
c. Current
d. Resistance
Correct answer: c. Current
Explanation:
Current = charge per second.
MCQ No. 25
Color code black represents:
a. 1
b. 2
c. 0
d. 5
Correct answer: c. 0
Explanation:
Black band corresponds to zero.
MCQ No. 26
The resistivity of a material depends on:
a. Length
b. Area
c. Temperature
d. Both material and temperature
Correct answer: d. Both material and temperature
Explanation:
Resistivity is independent of dimensions but depends on nature of material and temperature.
MCQ No. 27
For metallic conductors, resistance with rise of temperature:
a. Decreases
b. Remains same
c. Increases
d. Becomes zero
Correct answer: c. Increases
Explanation:
Metals have positive temperature coefficient of resistance.
MCQ No. 28
Unit of temperature coefficient of resistance is:
a. Ω
b. K
c. K⁻¹
d. m
Correct answer: c. K⁻¹
Explanation:
Temperature coefficient has unit per kelvin.
MCQ No. 29
Which material has negative temperature coefficient?
a. Copper
b. Iron
c. Tungsten
d. Silicon
Correct answer: d. Silicon
Explanation:
Semiconductors like silicon show decrease in resistance with temperature.
MCQ No. 30
A thermistor is:
a. Fixed resistor
b. Variable resistor
c. Heat sensitive resistor
d. Capacitor
Correct answer: c. Heat sensitive resistor
Explanation:
Thermistors change resistance with temperature.
MCQ No. 31
Conductivity is reciprocal of:
a. Resistance
b. Resistivity
c. Current
d. Voltage
Correct answer: b. Resistivity
Explanation:
σ = 1/ρ.
MCQ No. 32
SI unit of conductivity is:
a. Ω m
b. Ω⁻¹ m⁻¹
c. A/m
d. V/m
Correct answer: b. Ω⁻¹ m⁻¹
Explanation:
Conductivity unit is mho m⁻¹ or Ω⁻¹ m⁻¹.
MCQ No. 33
When a wire is stretched to double its length, its resistance becomes:
a. 2R
b. 3R
c. 4R
d. R/2
Correct answer: c. 4R
Explanation:
Length doubles, area halves → R becomes four times.
MCQ No. 34
Internal resistance of a cell is due to:
a. Electrodes
b. External wires
c. Electrolyte
d. Terminal
Correct answer: c. Electrolyte
Explanation:
Electrolyte opposes current inside the cell.
MCQ No. 35
Terminal potential difference of a cell during discharge is:
a. Greater than EMF
b. Equal to EMF
c. Less than EMF
d. Zero
Correct answer: c. Less than EMF
Explanation:
Some voltage drops across internal resistance.
MCQ No. 36
Electric power is given by:
a. I/R
b. V/I
c. VI
d. IR
Correct answer: c. VI
Explanation:
Power P = VI.
MCQ No. 37
Maximum power is transferred when:
a. Load resistance is zero
b. Load resistance is infinite
c. Load resistance equals internal resistance
d. Load resistance is half
Correct answer: c. Load resistance equals internal resistance
Explanation:
Condition for maximum power transfer: R = r.
MCQ No. 38
Potential divider is used to:
a. Increase voltage
b. Measure current
c. Obtain required voltage
d. Store energy
Correct answer: c. Obtain required voltage
Explanation:
Potential divider provides fraction of supply voltage.
MCQ No. 39
Wire-wound variable resistor is called:
a. Ammeter
b. Rheostat
c. Voltmeter
d. Galvanometer
Correct answer: b. Rheostat
Explanation:
Rheostat controls current by changing resistance.
MCQ No. 40
Heat produced in conductor is given by:
a. Q = IRt
b. Q = VIt
c. Q = I²Rt
d. Q = VR
Correct answer: c. Q = I²Rt
Explanation:
This is Joule’s law of heating.
MCQ No. 41
Which device converts heat energy into electrical energy?
a. Thermistor
b. Rheostat
c. Thermocouple
d. Voltmeter
Correct answer: c. Thermocouple
Explanation:
Thermocouple produces EMF due to temperature difference.
MCQ No. 42
Electric energy is measured in:
a. Joule
b. Watt
c. Ampere
d. Volt
Correct answer: a. Joule
Explanation:
Electrical energy is measured in joules.
MCQ No. 43
If radius of wire becomes half, resistance becomes:
a. 2R
b. 4R
c. 8R
d. 16R
Correct answer: d. 16R
Explanation:
Area becomes 1/4 and length increases → total factor 16.
MCQ No. 44
In parallel combination, equivalent resistance is:
a. Greater than largest
b. Equal to largest
c. Less than smallest
d. Equal to sum
Correct answer: c. Less than smallest
Explanation:
Parallel reduces total resistance.
MCQ No. 45
Unit of EMF is:
a. Ampere
b. Joule
c. Volt
d. Ohm
Correct answer: c. Volt
Explanation:
EMF is measured in volts.
MCQ No. 46
Current through equal resistors in parallel is:
a. Same
b. Different
c. Zero
d. Infinite
Correct answer: a. Same
Explanation:
Each branch has same voltage and resistance.
MCQ No. 47
Specific resistance is another name for:
a. Conductivity
b. Resistance
c. Resistivity
d. Conductance
Correct answer: c. Resistivity
Explanation:
Specific resistance means resistivity.
MCQ No. 48
If fourth band of resistor is missing, tolerance is:
a. ±5%
b. ±10%
c. ±20%
d. ±15%
Correct answer: c. ±20%
Explanation:
No band means ±20% tolerance.
MCQ No. 49
Conventional current flows from:
a. Negative to positive
b. Lower to higher potential
c. Higher to lower potential
d. Electron to proton
Correct answer: c. Higher to lower potential
Explanation:
Conventional current direction is from + to −.
MCQ No. 50
Slope of V–I graph gives:
a. Conductance
b. Resistivity
c. Resistance
d. Power
Correct answer: a. Conductance
Explanation:
Slope = I/V = conductance.
MCQ No. 51
Kirchhoff’s first law is based on conservation of:
a. Energy
b. Charge
c. Momentum
d. Mass
Correct answer: b. Charge
Explanation:
Kirchhoff’s Current Law (KCL) states that total current entering a junction equals total current leaving it, based on conservation of charge.
MCQ No. 52
Kirchhoff’s second law is based on conservation of:
a. Charge
b. Energy
c. Mass
d. Momentum
Correct answer: b. Energy
Explanation:
Kirchhoff’s Voltage Law (KVL) follows conservation of energy around a closed loop.
MCQ No. 53
Wheatstone bridge is used to measure:
a. Current
b. Voltage
c. Unknown resistance
d. Power
Correct answer: c. Unknown resistance
Explanation:
Balanced Wheatstone bridge determines unknown resistance accurately.
MCQ No. 54
A Wheatstone bridge is balanced when:
a. P + Q = R + S
b. P/Q = R/S
c. P = Q = R = S
d. PR = QS
Correct answer: b. P/Q = R/S
Explanation:
Bridge balance condition is ratio equality.
MCQ No. 55
Potentiometer works on principle that:
a. V ∝ I
b. V ∝ R
c. V ∝ l
d. I ∝ l
Correct answer: c. V ∝ l
Explanation:
Potential difference is proportional to wire length.
MCQ No. 56
Main advantage of potentiometer over voltmeter is:
a. Smaller size
b. Cheaper
c. No current drawn
d. Faster reading
Correct answer: c. No current drawn
Explanation:
Potentiometer measures voltage without drawing current.
MCQ No. 57
Drift velocity of electrons is:
a. Very large
b. Equal to speed of light
c. Very small
d. Infinite
Correct answer: c. Very small
Explanation:
Drift velocity is of order 10⁻³ m/s.
MCQ No. 58
EMF of a cell is defined as:
a. Terminal voltage
b. Energy per coulomb
c. Current produced
d. Resistance offered
Correct answer: b. Energy per coulomb
Explanation:
EMF = work done per unit charge.
MCQ No. 59
Internal resistance depends on:
a. Area of electrodes
b. Distance between electrodes
c. Nature of electrolyte
d. All of these
Correct answer: d. All of these
Explanation:
All listed factors affect internal resistance.
MCQ No. 60
Terminal voltage during charging is:
a. Less than EMF
b. Equal to EMF
c. Greater than EMF
d. Zero
Correct answer: c. Greater than EMF
Explanation:
Extra voltage is needed to overcome internal resistance.
MCQ No. 61
Electric power in resistor is:
a. V/I
b. I/R
c. V²/R
d. R/V
Correct answer: c. V²/R
Explanation:
Power P = V²/R.
MCQ No. 62
Unit of electric power is:
a. Joule
b. Volt
c. Watt
d. Ampere
Correct answer: c. Watt
Explanation:
SI unit of power is watt.
MCQ No. 63
Thermoelectric EMF is produced due to:
a. Magnetic field
b. Chemical action
c. Temperature difference
d. Pressure
Correct answer: c. Temperature difference
Explanation:
Temperature gradient between junctions creates EMF.
MCQ No. 64
Resistance thermometer works on:
a. Change of EMF
b. Change of resistance
c. Change of current
d. Change of charge
Correct answer: b. Change of resistance
Explanation:
Metal resistance varies with temperature.
MCQ No. 65
If two resistors are in series, total resistance is:
a. Product
b. Difference
c. Sum
d. Reciprocal
Correct answer: c. Sum
Explanation:
Series resistances add.
MCQ No. 66
If resistors are in parallel, equivalent resistance is found by:
a. Adding
b. Subtracting
c. Product/sum
d. Multiplying
Correct answer: c. Product/sum
Explanation:
Parallel formula uses reciprocal or product/sum.
MCQ No. 67
Charge on electron is:
a. 1 C
b. 1.6×10⁻¹⁹ C
c. 10⁻³ C
d. Zero
Correct answer: b. 1.6×10⁻¹⁹ C
Explanation:
Fundamental charge value.
MCQ No. 68
Current is defined as:
a. Energy/time
b. Charge/time
c. Voltage/resistance
d. Resistance/voltage
Correct answer: b. Charge/time
Explanation:
I = Q/t.
MCQ No. 69
Electric energy is commercially measured in:
a. Joule
b. Watt
c. kWh
d. Ampere
Correct answer: c. kWh
Explanation:
Domestic energy billing uses kilowatt-hour.
MCQ No. 70
Resistance of ideal ammeter is:
a. Infinite
b. Very large
c. Zero
d. Moderate
Correct answer: c. Zero
Explanation:
Ideal ammeter should not affect current.
MCQ No. 71
Resistance of ideal voltmeter is:
a. Zero
b. Infinite
c. Small
d. Equal to load
Correct answer: b. Infinite
Explanation:
So it draws no current.
MCQ No. 72
Wheatstone bridge is based on:
a. Ohm’s law
b. Kirchhoff’s 1st law
c. Kirchhoff’s 2nd law
d. Both B and C
Correct answer: d. Both B and C
Explanation:
Bridge analysis uses both Kirchhoff laws.
MCQ No. 73
Potential divider is a combination of:
a. Parallel resistors
b. Series resistors
c. Capacitors
d. Inductors
Correct answer: b. Series resistors
Explanation:
Voltage divides across series resistors.
MCQ No. 74
Thermocouple converts:
a. Electrical to heat
b. Heat to electrical
c. Mechanical to electrical
d. Chemical to electrical
Correct answer: b. Heat to electrical
Explanation:
Temperature difference generates EMF.
MCQ No. 75
Drift velocity increases when:
a. Temperature increases
b. Electric field increases
c. Resistance increases
d. Length increases
Correct answer: b. Electric field increases
Explanation:
Drift velocity ∝ electric field.
MCQ No. 76
Drift velocity of electrons is directly proportional to:
a. Resistance
b. Electric field
c. Length of conductor
d. Area of conductor
Correct answer: b. Electric field
Explanation:
Drift velocity increases with electric field strength applied across the conductor.
MCQ No. 77
If temperature of a metallic wire increases, its resistivity:
a. Decreases
b. Becomes zero
c. Remains constant
d. Increases
Correct answer: d. Increases
Explanation:
For metals, resistivity rises with temperature due to increased lattice vibrations.
MCQ No. 78
Internal resistance of a cell becomes minimum when:
a. Electrodes are far apart
b. Electrolyte is diluted
c. Electrodes have small area
d. Electrodes have large area
Correct answer: d. Electrodes have large area
Explanation:
Larger electrode area provides more conducting paths, reducing internal resistance.
MCQ No. 79
Maximum power is delivered to external circuit when:
a. External resistance is zero
b. Internal resistance is zero
c. External resistance equals internal resistance
d. External resistance is infinite
Correct answer: c. External resistance equals internal resistance
Explanation:
According to maximum power transfer theorem, R = r gives maximum output power.
MCQ No. 80
Kirchhoff’s Voltage Law states that algebraic sum of voltages in closed loop is:
a. Maximum
b. Unity
c. Infinite
d. Zero
Correct answer: d. Zero
Explanation:
Energy conservation requires total potential rise equals total drop.
MCQ No. 81
Balance condition of Wheatstone bridge is:
a. P/Q = R/S
b. P+Q = R+S
c. PQ = RS
d. P/Q = S/R
Correct answer: a. P/Q = R/S
Explanation:
Bridge is balanced when ratio of resistances in both arms is equal.
MCQ No. 82
Sensitivity of potentiometer increases when:
a. Wire length decreases
b. Potential gradient increases
c. Potential gradient decreases
d. Current increases
Correct answer: c. Potential gradient decreases
Explanation:
Lower potential gradient allows more precise voltage measurement.
MCQ No. 83
Thermocouple works on:
a. Joule effect
b. Seebeck effect
c. Hall effect
d. Photoelectric effect
Correct answer: b. Seebeck effect
Explanation:
Temperature difference between junctions produces EMF.
MCQ No. 84
Electric power consumed in resistor is:
a. I/R
b. V/I
c. VI
d. R/I
Correct answer: c. VI
Explanation:
Power equals product of voltage and current.
MCQ No. 85
Resistance thermometer operates on variation of:
a. Voltage
b. EMF
c. Resistance
d. Power
Correct answer: c. Resistance
Explanation:
Metal resistance changes with temperature.
MCQ No. 86
Conductivity is reciprocal of:
a. Resistance
b. Conductance
c. Resistivity
d. Current
Correct answer: c. Resistivity
Explanation:
Conductivity = 1 / resistivity.
MCQ No. 87
Unit of temperature coefficient of resistance is:
a. Ω
b. °C
c. °C⁻¹
d. V
Correct answer: c. °C⁻¹
Explanation:
It represents fractional change in resistance per degree.
MCQ No. 88
If length of wire is doubled and area halved, resistance becomes:
a. Same
b. Double
c. Four times
d. Half
Correct answer: c. Four times
Explanation:
R ∝ L/A → doubling L and halving A makes R four times.
MCQ No. 89
Potential divider provides:
a. Constant current
b. Variable voltage
c. High resistance
d. Maximum power
Correct answer: b. Variable voltage
Explanation:
It divides applied voltage into required fractions.
MCQ No. 90
Wire-wound variable resistor is called:
a. Thermistor
b. Rheostat
c. Capacitor
d. Inductor
Correct answer: b. Rheostat
Explanation:
Rheostats vary current by changing resistance.
MCQ No. 91
Kirchhoff’s Current Law is based on conservation of:
a. Energy
b. Charge
c. Mass
d. Power
Correct answer: b. Charge
Explanation:
Total current entering equals total leaving a junction.
MCQ No. 92
Drift velocity of electrons is very:
a. High
b. Equal to light speed
c. Low
d. Infinite
Correct answer: c. Low
Explanation:
Electron drift speed is extremely small compared to signal speed.
MCQ No. 93
EMF of cell is measured when:
a. Current flows
b. Circuit is closed
c. Circuit is open
d. Resistance is zero
Correct answer: c. Circuit is open
Explanation:
EMF is open-circuit voltage.
MCQ No. 94
Thermistor shows:
a. Positive temperature coefficient
b. Zero temperature coefficient
c. Negative temperature coefficient
d. Infinite coefficient
Correct answer: c. Negative temperature coefficient
Explanation:
Thermistor resistance decreases as temperature rises.
MCQ No. 95
Specific resistance depends on:
a. Length
b. Area
c. Shape
d. Nature of material
Correct answer: d. Nature of material
Explanation:
Resistivity is material property.
MCQ No. 96
Unit of EMF is:
a. Ampere
b. Ohm
c. Volt
d. Watt
Correct answer: c. Volt
Explanation:
EMF represents energy per unit charge.
MCQ No. 97
Thermoelectric EMF varies with:
a. Current
b. Resistance
c. Temperature difference
d. Area
Correct answer: c. Temperature difference
Explanation:
Greater temperature difference gives higher EMF.
MCQ No. 98
Potentiometer is more accurate because it:
a. Uses current
b. Draws no current
c. Has high resistance
d. Produces power
Correct answer: b. Draws no current
Explanation:
Null method avoids loading error.
MCQ No. 99
Electric power unit is:
a. Volt
b. Ampere
c. Joule
d. Watt
Correct answer: d. Watt
Explanation:
Power is measured in watts.
MCQ No. 100
Conductance unit is:
a. Ohm
b. Volt
c. Siemens
d. Ampere
Correct answer: c. Siemens
Explanation:
Conductance is reciprocal of resistance and its SI unit is siemens.
20 more miscellaneous Basic MCQs on Current and Electricity
MCQ No. 1
Drift velocity of electrons in a conductor increases when:
a. Length is increased
b. Area is increased
c. Electric field is increased
d. Temperature is increased
Correct answer: c. Electric field is increased
Explanation:
Drift velocity is directly proportional to the applied electric field.
MCQ No. 2
Unit of electrical conductivity is:
a. Ω m
b. Ω/m
c. S m⁻¹
d. V/A
Correct answer: c. S m⁻¹
Explanation:
Conductivity is reciprocal of resistivity and its SI unit is siemens per meter.
MCQ No. 3
If resistance of a wire is doubled, its conductance becomes:
a. Double
b. Same
c. Half
d. Four times
Correct answer: c. Half
Explanation:
Conductance is inverse of resistance.
MCQ No. 4
Resistance of metallic conductors usually:
a. Decreases with temperature
b. Remains constant
c. Increases with temperature
d. Becomes zero
Correct answer: c. Increases with temperature
Explanation:
For metals, resistance rises as temperature increases.
MCQ No. 5
Temperature coefficient of resistance has unit:
a. °C
b. Ω
c. °C⁻¹
d. V
Correct answer: c. °C⁻¹
Explanation:
It represents change in resistance per degree temperature.
MCQ No. 6
Specific resistance depends on:
a. Length
b. Area
c. Material only
d. Shape
Correct answer: c. Material only
Explanation:
Resistivity is a property of material.
MCQ No. 7
A thermistor is mainly used to measure:
a. Voltage
b. Current
c. Temperature
d. Power
Correct answer: c. Temperature
Explanation:
Thermistors are temperature-sensitive resistors.
MCQ No. 8
EMF of a cell is defined as:
a. Terminal voltage
b. Work done per unit charge
c. Current per unit resistance
d. Power per charge
Correct answer: b. Work done per unit charge
Explanation:
EMF equals energy supplied per coulomb.
MCQ No. 9
Internal resistance of a cell depends on:
a. External circuit
b. Shape of conductor
c. Electrolyte and electrodes
d. Voltage
Correct answer: c. Electrolyte and electrodes
Explanation:
Nature and separation of electrodes affect internal resistance.
MCQ No. 10
Electric power is given by:
a. V/R
b. I/R
c. VI
d. R/I
Correct answer: c. VI
Explanation:
Power equals voltage multiplied by current.
MCQ No. 11
Maximum power is transferred when:
a. R > r
b. R < r
c. R = r
d. R = 0
Correct answer: c. R = r
Explanation:
Maximum power condition is load resistance equals internal resistance.
MCQ No. 12
Thermocouples work on principle of:
a. Magnetic effect
b. Joule heating
c. Seebeck effect
d. Photoelectric effect
Correct answer: c. Seebeck effect
Explanation:
Temperature difference produces EMF in thermocouples.
MCQ No. 13
Kirchhoff’s current law is based on conservation of:
a. Energy
b. Charge
c. Momentum
d. Mass
Correct answer: b. Charge
Explanation:
Total current entering a junction equals leaving current.
MCQ No. 14
Kirchhoff’s voltage law is based on conservation of:
a. Charge
b. Mass
c. Energy
d. Power
Correct answer: c. Energy
Explanation:
Sum of potential differences in a closed loop is zero.
MCQ No. 15
Wheatstone bridge is used to measure:
a. Current
b. Voltage
c. Unknown resistance
d. Power
Correct answer: c. Unknown resistance
Explanation:
Balanced bridge gives precise resistance values.
MCQ No. 16
Potentiometer works on principle that potential drop is proportional to:
a. Resistance
b. Current
c. Length
d. Area
Correct answer: c. Length
Explanation:
Uniform wire gives uniform potential gradient.
MCQ No. 17
Sensitivity of potentiometer increases with:
a. Thick wire
b. Short wire
c. Small potential gradient
d. High current
Correct answer: c. Small potential gradient
Explanation:
Lower gradient improves accuracy.
MCQ No. 18
Resistance thermometer is based on change of:
a. Voltage
b. Resistance
c. Current
d. EMF
Correct answer: b. Resistance
Explanation:
Metal resistance varies with temperature.
MCQ No. 19
Potential divider is used to obtain:
a. Constant current
b. Variable voltage
c. Maximum power
d. High resistance
Correct answer: b. Variable voltage
Explanation:
It divides voltage in required ratio.
MCQ No. 20
Wire-wound variable resistors are also called:
a. Rheostats
b. Capacitors
c. Inductors
d. Fuses
Correct answer: a. Rheostats
Explanation:
Rheostats vary resistance mechanically.
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