Electromagnetic Theory and Fields MCQs 2026

Gauss law for electricity states

1. A electric flux through closed surface equals enclosed charge divided by epsilon ✓
2. B B dot dA equals zero always ✓
3. C E equals zero everywhere ✓
4. D charge creates no field ✓

Gauss law for magnetism states

1. A magnetic flux through any closed surface is zero ✓
2. B magnetic monopoles exist always ✓
3. C flux equals enclosed current ✓
4. D B equals H always ✓

Faraday law of induction states

1. A flux is constant always ✓
2. B induced EMF equals negative rate of change of magnetic flux linkage ✓
3. C EMF equals IR only ✓
4. D current creates no EMF ✓

Ampere law (with Maxwell correction) relates

1. A only conduction current without displacement ✓
2. B only electric charge density ✓
3. C only static fields ✓
4. D circulation of H to conduction plus displacement current ✓

Maxwell added displacement current because

1. A magnetic monopoles exist ✓
2. B changing electric field in capacitor gap sustains magnetic field ✓
3. C Faraday law fails in DC ✓
4. D Gauss law fails in vacuum ✓

Magnetic flux phi equals

1. A B dot A (B times A for uniform normal field) ✓
2. B H times l only ✓
3. C I times R ✓
4. D V times C ✓

Self-inductance L equals

1. A I divided by flux ✓
2. B flux linkage divided by current (N phi / I) ✓
3. C R times C ✓
4. D V times I ✓

Energy stored in inductor is

1. A one half L I squared ✓
2. B L I ✓
3. C I squared R only ✓
4. D V Q only ✓

Magnetic field intensity H relates to B by

1. A B = mu H ✓
2. B B = H/R ✓
3. C H = B squared ✓
4. D B equals H always in vacuum only without mu ✓

Relative permeability mu_r is

1. A mu0/mu ✓
2. B mu/mu0 ratio ✓
3. C B/H always 1 ✓
4. D conductivity ratio ✓

Lenz law states induced current direction

1. A aids the change always ✓
2. B is random ✓
3. C follows only resistor rule ✓
4. D opposes the change causing it ✓

Displacement current density is

1. A conduction J only ✓
2. B B times A ✓
3. C rate of change of electric flux density (dD/dt) ✓
4. D H times l ✓

Magnetic flux density unit is

1. A tesla (T) or weber per square meter ✓
2. B henry ✓
3. C farad ✓
4. D siemens ✓

Magnetomotive force (MMF) equals

1. A B A only ✓
2. B N I ampere-turns ✓
3. C phi/R only ✓
4. D V/R always ✓

Reluctance Rm in magnetic circuit analog to

1. A capacitance ✓
2. B resistance in electric circuit ✓
3. C inductance only ✓
4. D voltage source ✓

Faraday law explains operation of

1. A transformers and generators ✓
2. B pure resistors only ✓
3. C Wheatstone bridge only ✓
4. D DC resistive dividers only ✓

Coulomb law gives electric force

1. A proportional to r squared ✓
2. B independent of distance ✓
3. C proportional to q1 q2 over r squared ✓
4. D only magnetic ✓

Electric flux density D equals

1. A mu H ✓
2. B B only ✓
3. C J always ✓
4. D epsilon E (in linear isotropic medium) ✓

Biot-Savart law gives B from

1. A static charge only ✓
2. B capacitor voltage only ✓
3. C current element geometry ✓
4. D resistor color code ✓

Ampere circuital law for steady conduction is

1. A closed E dl equals dB/dt ✓
2. B flux zero always ✓
3. C D equals rho ✓
4. D closed H dl equals enclosed current ✓

Right-hand rule for magnetic field around wire relates

1. A B parallel to current always ✓
2. B thumb current, curled fingers B direction ✓
3. C E and B same direction ✓
4. D flux zero always ✓

Magnetic materials with mu_r much greater than 1 are

1. A ferromagnetic (e.g. iron) ✓
2. B perfect vacuum ✓
3. C superconductors only ✓
4. D perfect insulators only ✓

Hysteresis loop area represents

1. A energy loss per cycle in core ✓
2. B stored inductance only ✓
3. C capacitance only ✓
4. D charge on plates ✓

Eddy currents in core are reduced by

1. A solid thick core ✓
2. B laminated core sheets ✓
3. C increasing frequency always ✓
4. D removing insulation ✓

Magnetic flux unit is

1. A tesla only ✓
2. B henry only ✓
3. C ampere only ✓
4. D weber (Wb) ✓

Permeability of free space mu0 approx

1. A 10^-12 F/m ✓
2. B 377 ohm ✓
3. C 1 H/m ✓
4. D 4 pi times 10^-7 H/m ✓

Electric field E unit is

1. A tesla ✓
2. B volts per meter ✓
3. C weber ✓
4. D henry ✓

Maxwell equations unify

1. A only DC resistors ✓
2. B only mechanics ✓
3. C electric and magnetic fields with sources and time variation ✓
4. D only thermal energy ✓

Static charge produces

1. A curl E nonzero always ✓
2. B divergence of D equal to rho (Gauss electric) ✓
3. C B monopoles ✓
4. D displacement current only ✓

Time-varying B produces

1. A zero E always ✓
2. B only D ✓
3. C only H static ✓
4. D curl E (Faraday) ✓

Magnetic flux linkage lambda equals

1. A phi divided by N always ✓
2. B B only ✓
3. C N times phi for N turns ✓
4. D H l only ✓

Inductance of solenoid increases with

1. A fewer turns only ✓
2. B shorter length with same N always decreases L ✓
3. C more turns and larger cross-section and core permeability ✓
4. D air gap removal never matters ✓

Energy density in magnetic field is

1. A one half B H (or B squared over 2 mu) ✓
2. B B times A only ✓
3. C I R only ✓
4. D Q V only ✓

Poynting vector represents

1. A static charge only ✓
2. B DC resistance only ✓
3. C only displacement current without E ✓
4. D direction and density of EM power flow ✓

Boundary condition: tangential E is

1. A always zero ✓
2. B discontinuous always ✓
3. C continuous across interface (ideal) ✓
4. D equal to B ✓

Boundary condition: normal B is

1. A always zero ✓
2. B discontinuous always ✓
3. C continuous (no monopoles) ✓
4. D equals H ✓

Magnetic vector potential A relates to B as

1. A B = div A ✓
2. B A = curl B ✓
3. C A equals phi ✓
4. D B = curl A ✓

Electric scalar potential V relates to E as

1. A E equals V times I ✓
2. B V equals B A ✓
3. C E = negative gradient of V ✓
4. D E equals curl V ✓

Displacement current exists in

1. A pure resistor only ✓
2. B capacitor dielectric between plates during charging ✓
3. C short circuit wire only ✓
4. D permanent magnet only ✓

Magnetic circuit Ohm law analog: flux equals

1. A MMF times reluctance ✓
2. B NI squared ✓
3. C MMF divided by reluctance ✓
4. D B only without area ✓