All Free Electrical Engineering MCQs with Answers

• A. in the direction of electric intensity
• B. against electric intensity
• C. in any direction
• D. in the direction of electric flux

Explanation: Potential difference is the work done per unit positive charge when it is moved against the electric field.

• A. voltage applied
• B. thickness of the capacitor plates
• C. geometry of the capacitor
• D. dinsity of the capacitor plates

Explanation: For an ideal capacitor, capacitance is determined by its geometry and the dielectric material between its plates, not by the applied…

• A. Nm2C2
• B. N-1mC-2
• C. NmC-1
• D. N-1m-2C2

Explanation: From Coulomb’s law, ε₀ has units C²/(N·m²), equivalently N⁻¹m⁻²C². This corresponds to option d.

• A. 1/4IIɛ q/r
• B. q/ɛ0
• C. 1/4IIɛ0. q/r2
• D. 4IIɛ0

Explanation: Gauss’s law gives the total electric flux from a point charge q as Φ = q/ε₀, independent of the radius of the enclosing spherical surface.

• A. V/A
• B. J/V
• C. V/m
• D. A/m

Explanation: Since 1 volt equals 1 joule per coulomb and 1 newton equals 1 joule per metre, N/C simplifies to V/m.

• A. Electrostatics
• B. Charges in motion
• C. Capacitors
• D. Electric fieldsLearn Quantum Physics

Explanation: Photocopiers and inkjet printers use electrostatic charging and attraction of toner or ink particles to place an image.

• A. Remains same
• B. First increases then decreases
• C. Decreases then increases
• D. Increases for a whileHire Civil Engineers

Explanation: A negatively charged conductor has gained electrons, and the added electron mass makes its weight increase slightly.

• A. Decreases 9 times
• B. Increases 9 times
• C. Increases 4 times
• D. Decreases 4 times

Explanation: From Coulomb’s law, force is proportional to the product of the two charges, F ∝ q₁q₂.

• A. increases
• B. decreases
• C. increases then decreases
• D. decreases then increasesCompare Local Schools

Explanation: Mica acts as a dielectric between the plates, increasing the relative permittivity while the geometry remains unchanged.

• A. electric flux
• B. electric intensity
• C. electric potential
• D. all of above are same

Explanation: Electric field intensity is defined as force per unit positive test charge, E = F/q.

• A. decrease
• B. increase
• C. remain constant
• D. depends upon composition of dielectricEngineering & Technology

Explanation: In a dielectric, Coulomb force becomes F/εr relative to its value in vacuum, so it decreases when the relative permittivity is greater…

• A. glass rod acquires negative charge while silk acquires positive charge
• B. glass rod acquires positive charge while silk acquires negative charges
• C. both glass rod and silk acquire negative charge
• D. both glass rod and silk acquire positive charge

Explanation: Rubbing transfers electrons from the glass to the silk. The glass therefore becomes positively charged and the silk negatively charged…

• A. ωB/r22-r12/Δt
• B. ωB(r2-r1)2/Δt
• C. ωB(r22-r12)/Δt
• D. ωB(r22+r12)/Δt

Explanation: With the coil's plane perpendicular to the field, flux is Bπr². Thus the induced emf magnitude is Bπ(r₂² − r₁²)/Δt, corresponding to…

• A. 0 volt
• B. 3.125 volt
• C. 31.25 volt
• D. 0.03125 volt

Explanation: For a rod moving perpendicular to a magnetic field, the motional emf is E = Blv = 0.25 × 0.25 × 0.5 = 0.03125 V.

• A. Decreases the resistance of the solenoid
• B. Reduces the effect of eddy current
• C. Improves the flux linkage between the turns of the coil
• D. Increases the mutual inductance between the solenoid and the coreElectricity

Explanation: A soft iron core has high permeability, concentrating magnetic flux through the solenoid and increasing the flux linkage per unit current.

• A. Mutual inductance
• B. Self inductance
• C. Magnetic fields
• D. Heating effect

Explanation: A non-inductive resistor is wound so that the magnetic fields of adjacent sections cancel, making its net inductance very small.

• A. AC
• B. DC
• C. Both A and B
• D. none of these

Explanation: After the transient has died out, an ideal inductor has zero voltage across it because v = L(di/dt) and steady DC current has constant…

• A. maximum magnetic flux
• B. rate of change of magnetic flux
• C. change in magnetic flux
• D. initial magnetic flux

Explanation: Faraday’s law states that induced emf is proportional to the rate of change of magnetic flux, expressed as e = -N(dΦ/dt).

• A. solve for all the voltage drops
• B. solve for the total current and resistance
• C. equate all series components
• D. equate all parallel components

Explanation: A complex series-parallel circuit is first reduced to an equivalent total resistance, after which the source current can be found using…

• A. circuit diagram
• B. battery knobs
• C. battery terminals
• D. battery sides

Explanation: The two points where a battery connects to an external circuit are its terminals, conventionally marked positive and negative.