Magnetism and Electromagnetism MCQs 2026

Eddy currents are

1. ACurrents that flow only in wires✓
2. BUseful in reducing all energy losses✓
3. CInduced circulating currents in a conductor due to changing magnetic flux✓
4. DCurrents that flow only in insulators✓

A DC motor converts

1. AMechanical energy into electrical energy✓
2. BHeat into mechanical energy✓
3. CChemical energy into mechanical energy✓
4. DElectrical energy into mechanical energy✓

According to Lenz's law, if the north pole of a magnet is pushed towards a coil, the near face of the coil develops a

1. ASouth pole, attracting the magnet✓
2. BNo pole at all✓
3. CNorth pole, opposing the approaching magnet✓
4. DSouth pole, but no force✓

An AC generator converts

1. AMechanical energy into electrical energy✓
2. BElectrical energy into mechanical energy✓
3. CChemical energy into electrical energy✓
4. DHeat energy into electrical energy✓

The area enclosed in a hysteresis loop represents the

1. ATotal magnetic flux✓
2. BEnergy lost as heat per cycle of magnetization✓
3. CRetentivity of the material✓
4. DCoercive force✓

The unit tesla is equivalent to

1. AOne weber per second✓
2. BOne ampere per metre✓
3. COne henry per second✓
4. DOne weber per square metre✓

Magnetic shielding is used to

1. AIncrease magnetic field strength✓
2. BGenerate additional current✓
3. CConvert AC to DC✓
4. DProtect sensitive devices from external magnetic fields✓

MRI (Magnetic Resonance Imaging) machines primarily rely on

1. AX-rays✓
2. BRadioactive decay✓
3. CStrong magnetic fields and radio waves✓
4. DUltraviolet radiation✓

The working of a moving coil galvanometer is based on the

1. APhotoelectric effect✓
2. BTorque experienced by a current-carrying coil in a magnetic field✓
3. CThermoelectric effect✓
4. DElectrolysis✓

A cyclotron is a device used to

1. AMeasure magnetic field strength✓
2. BGenerate AC power✓
3. CStore electrical energy✓
4. DAccelerate charged particles to high energies using magnetic and electric fields✓

Unlike a permanent magnet, an electromagnet's magnetic field can be

1. ASwitched on and off by controlling the current✓
2. BNever changed✓
3. COnly increased, never decreased✓
4. DReversed only by heating✓

Above the Curie temperature, a ferromagnetic material

1. ABecomes superconducting✓
2. BLoses its ferromagnetism and becomes paramagnetic✓
3. CBecomes strongly diamagnetic✓
4. DMelts instantly✓

Ferromagnetic materials such as iron, cobalt, and nickel are

1. AWeakly attracted✓
2. BWeakly repelled✓
3. CStrongly attracted by a magnetic field✓
4. DUnaffected by magnetic fields✓

Paramagnetic materials are

1. AWeakly attracted by a magnetic field✓
2. BStrongly repelled by a magnetic field✓
3. CUnaffected by magnetic fields✓
4. DStrongly attracted like iron✓

Diamagnetic materials, when placed in a magnetic field, are

1. AStrongly attracted✓
2. BStrongly repelled and retain magnetism✓
3. CAttracted weakly✓
4. DWeakly repelled✓

The SI unit of magnetic flux is the

1. ATesla✓
2. BHenry✓
3. CWeber✓
4. DAmpere-turn✓

Magnetic flux is defined as the product of magnetic field and

1. AResistance✓
2. BArea perpendicular to the field✓
3. CCurrent✓
4. DVoltage✓

The magnetic field inside a long solenoid is given by B = mu-naught times n times I, where n represents

1. ANumber of turns per unit length✓
2. BTotal number of turns✓
3. CTotal current✓
4. DRadius of the solenoid✓

In a toroid, the magnetic field is mostly confined

1. AInside the toroidal core✓
2. BOutside the toroid only✓
3. CNowhere, it cancels out✓
4. DEqually inside and outside✓

The magnetic field pattern outside a current-carrying solenoid closely resembles that of a

1. AStraight wire✓
2. BToroid✓
3. CSingle loop✓
4. DBar magnet✓

The EMF induced in a conductor moving through a magnetic field is called

1. AStatic EMF✓
2. BMotional EMF✓
3. CBack EMF✓
4. DThermal EMF✓

Ferromagnetism arises due to the presence of

1. AFree electrons only✓
2. BIonic bonds✓
3. CCovalent bonds✓
4. DMagnetic domains that align in an external field✓

Like magnetic poles

1. AAttract each other✓
2. BHave no interaction✓
3. CRepel each other✓
4. DNeutralize each other✓

Coercivity refers to the

1. AMaximum magnetic flux a material can hold✓
2. BAbility to conduct current✓
3. CRetained magnetism after removing the field✓
4. DReverse magnetic field required to demagnetize a material completely✓

The imaginary plane passing through the magnetic north and south poles and a given point is called the

1. AGeographic meridian✓
2. BEquatorial plane✓
3. CMagnetic meridian✓
4. DNeutral plane✓

A neutral point near a bar magnet is a location where

1. AMagnetic field is maximum✓
2. BThe magnet's field exactly cancels the Earth's horizontal magnetic field✓
3. COnly the Earth's field exists undisturbed✓
4. DTwo magnets attract most strongly✓

Soft iron is preferred over steel for making electromagnet cores because soft iron

1. AMagnetizes and demagnetizes quickly with low retentivity✓
2. BRetains magnetism permanently✓
3. CHas higher electrical resistance✓
4. DIs a better insulator✓

Faraday's law of electromagnetic induction states that induced EMF is proportional to the

1. AResistance of the coil✓
2. BCurrent through the coil✓
3. CNumber of turns only✓
4. DRate of change of magnetic flux✓

The standard frequency of AC mains supply in Pakistan is

1. A60 Hz✓
2. B100 Hz✓
3. C25 Hz✓
4. D50 Hz✓

The SI unit of magnetic field (flux density) is the

1. AWeber✓
2. BAmpere-turn✓
3. CTesla✓
4. DHenry✓

In a cyclotron, the time period of the charged particle's circular motion is

1. ADependent on its speed✓
2. BDependent on the radius of its path✓
3. CIndependent of its speed and radius✓
4. DDependent on its mass only, not charge✓

The force on a charge q moving with velocity v in a magnetic field B is given by

1. AF = qE✓
2. BF = qvB sin(theta)✓
3. CF = BIL✓
4. DF = q squared v B✓

The value of the permeability of free space (mu-naught) is approximately

1. A4 pi times 10 to the power minus 7 tesla-metre per ampere✓
2. B8.85 times 10 to the power minus 12 farad per metre✓
3. C9 times 10 to the power 9 newton metre squared per coulomb squared✓
4. D6.6 times 10 to the power minus 34 joule-second✓

A step-down transformer has

1. AMore turns in secondary than primary✓
2. BFewer turns in secondary than primary✓
3. CEqual turns in both coils✓
4. DNo coils at all✓

A step-up transformer increases voltage while

1. AKeeping current constant✓
2. BIncreasing current as well✓
3. CKeeping power output higher than input✓
4. DDecreasing current proportionally✓

The SI unit of self-inductance is the

1. AWeber✓
2. BTesla✓
3. CHenry✓
4. DFarad✓

Mutual induction occurs when a changing current in one coil induces an EMF in

1. AA neighboring coil✓
2. BThe same coil only✓
3. CA resistor✓
4. DA capacitor✓

Lenz's law states that the direction of induced current always opposes

1. AThe magnetic field✓
2. BThe change in magnetic flux that produces it✓
3. CThe resistance of the circuit✓
4. DThe applied voltage✓

Magnetic field lines around a bar magnet

1. ANever intersect each other✓
2. BAlways intersect at the center✓
3. CAre parallel straight lines only✓
4. DOriginate and end at the same pole✓

The direction of induced current in a generator is given by

1. AFleming's right-hand rule✓
2. BFleming's left-hand rule✓
3. CRight-hand thumb rule✓
4. DAmpere's law✓

The angle between the geographic meridian and the magnetic meridian at a place is called

1. AMagnetic dip✓
2. BMagnetic latitude✓
3. CRetentivity✓
4. DMagnetic declination✓

The force on a current-carrying conductor placed in a magnetic field is given by

1. AF = BIL sin(theta)✓
2. BF = qvB✓
3. CF = BQ✓
4. DF = IR✓

The angle made by the Earth's magnetic field with the horizontal at a place is called

1. ADeclination✓
2. BAngle of dip (inclination)✓
3. CLatitude✓
4. DLongitude✓

The direction of force on a current-carrying conductor in a magnetic field (motor effect) is given by

1. AFleming's right-hand rule✓
2. BLenz's law✓
3. CFleming's left-hand rule✓
4. DRight-hand thumb rule✓

Retentivity of a magnetic material refers to its ability to

1. ARetain magnetism after the external field is removed✓
2. BResist becoming magnetized✓
3. CLose magnetism instantly✓
4. DConduct electric current✓

Two parallel conductors carrying current in the same direction will

1. ARepel each other✓
2. BAttract each other✓
3. CShow no force✓
4. DRotate around each other✓

Ampere's circuital law relates the line integral of magnetic field around a closed loop to the

1. AVoltage across the loop✓
2. BMagnetic flux through the loop✓
3. CCurrent enclosed by the loop✓
4. DResistance of the loop✓

The Biot-Savart law is used to calculate the

1. AEMF induced in a coil✓
2. BForce on a moving charge✓
3. CResistance of a conductor✓
4. DMagnetic field due to a small current-carrying element✓

The direction of the magnetic field around a straight current-carrying conductor is given by

1. AFleming's left-hand rule✓
2. BRight-hand thumb rule✓
3. CLenz's law✓
4. DFleming's right-hand rule✓

Oersted's experiment demonstrated that

1. AAn electric current produces a magnetic field around it✓
2. BA magnetic field produces an electric current✓
3. CMagnets repel electrons✓
4. DCurrent has no magnetic effect✓