CBSE Class 12 Electromagnetism — practice questions
92 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice CBSE Class 12 Electromagnetism in the app →A proton moves north at $10^6$ m/s in a magnetic field of $0.1$ T pointing east. The magnetic force on it is:A long straight wire carries $5$ A. The magnetic field $0.10$ m away from the wire is:A solenoid has $500$ turns per metre and carries $2$ A. Field inside is:The cyclotron frequency of a particle of mass $m$ and charge $q$ in field $B$ is:Oersted's 1820 experiment showed that a current-carrying wire produces a noticeable effect on a nearbyThe magnetic force on a charge $q$ moving with velocity $\vec{v}$ in a magnetic field $\vec{B}$ isA positive charge moves with velocity $\vec{v}$ PARALLEL to a uniform magnetic field $\vec{B}$. The magnetic fThe Biot-Savart law gives the magnetic field $d\vec{B}$ due to a small current element $I\,d\vec{l}$ at a poinThe magnetic field at the CENTRE of a circular current loop of radius $R$ carrying current $I$ isInside a long solenoid carrying current $I$ with $n$ turns per unit length, the magnetic field isAmpere's Circuital Law states that around any CLOSED loop, the line integral of $\vec{B}\cdot d\vec{l}$ equalsA charged particle (charge $q$, mass $m$) moves in a circle perpendicular to a uniform magnetic field $B$. TheTwo long parallel wires separated by distance $d$ carry currents $I_1$ and $I_2$ in the SAME direction. The foA current loop of area $A$ carrying current $I$ has a MAGNETIC MOMENT of magnitudeA moving-coil galvanometer measures current by exploiting which physical principle?A charged particle enters a region of crossed electric and magnetic fields ($\vec{E}\perp\vec{B}$). For the paA charged particle of mass $m$ and charge $q$ enters a uniform magnetic field $B$ with velocity $\vec{v}$ at aThe magnetic field at a distance $r$ from a LONG STRAIGHT wire carrying current $I$ isA charged particle moves with velocity v parallel to a uniform magnetic field B. The magnetic force on the parA circular loop of radius R carries current I. The magnitude of the magnetic field at its centre isThe angular frequency of a particle of charge q and mass m moving in a cyclotron with magnetic field B isTwo long parallel wires carry currents in the same direction. They willThe magnetic field inside an ideal long solenoid with n turns per unit length carrying current I isIn a crossed E and B velocity selector, a charged particle of speed v passes undeflected when v equalsA proton of mass m, charge e, speed v enters a magnetic field B perpendicular to its velocity. The radius of iA rectangular current loop is placed in a uniform magnetic field. The net force on the loop isA circular coil of N turns and radius R carries current I. Its magnetic dipole moment isThe magnitude of the magnetic field at perpendicular distance r from an infinite straight wire carrying currenThe magnetic field inside a toroidal solenoid with N total turns, mean radius r, carrying current I isThe period of revolution of a charged particle moving in a uniform magnetic field perpendicular to its velocitA 0.5 m wire carrying 2 A is placed perpendicular to a 0.4 T magnetic field. The force on the wire isTwo long parallel wires 0.1 m apart carry 5 A and 10 A in the same direction. The force per unit length on eacAt equilibrium, the deflection ϕ of a moving coil galvanometer with N turns, area A, current I, in a radial maAn electron enters a uniform magnetic field B at angle θ to B with speed v. The pitch of its helical path isA cyclotron of dee radius R accelerates ions of charge q, mass m in a magnetic field B. The maximum kinetic enA circular loop of radius R carries current I. The magnetic field at a point on its axis at distance x from thAt the very end of a long solenoid, the magnetic field along the axis isA magnetic dipole with moment m makes angle θ with a uniform field B. The torque on the dipole has magnitudeAn electron moves east in a magnetic field directed north. The magnetic force on the electron pointsTwo coaxial circular loops of radii R and 2R carry equal currents in the same sense. The ratio of the magneticA cyclotron operates at frequency f in a magnetic field B. The charge-to-mass ratio of the accelerated ion isThe current sensitivity of a moving coil galvanometer with N turns, coil area A, magnetic field B, spring consA 0.1 m radius loop carries 5 A. The magnetic field at a point on its axis 0.1 m from the centre is approximatA bar magnet with N pole pointing right is placed near a circular current loop whose magnetic moment also poinCyclotrons are not used to accelerate electrons becauseA long solenoid has 1000 turns per metre and carries 2 A. The magnetic field strength inside isA square coil of side 0.1 m, with 50 turns, carries 1 A in a 0.2 T field. The maximum torque on the coil isA charge q moves with velocity v through a region with electric field E and magnetic field B. The net electromWho noticed that a current in a wire deflects a compass needle?In which year was that observation made?Oersted was a physicist from:Iron filings sprinkled around a current-carrying wire arrange in:Reversing the direction of the current reverses the needle's:Oersted concluded that moving charges or currents produce a:In which year were the laws of electricity and magnetism unified?The combined electric and magnetic force on a charge is called the:The magnetic part of the Lorentz force depends on charge, field and:The magnetic force on a negative charge, compared with a positive one, is:The magnetic force includes a product of velocity and field that is a:The SI unit of magnetic field is the:The tesla is named after:One gauss is equal to how many tesla?The cyclotron was invented in the year:The cyclotron was invented by E.O. Lawrence and:The cyclotron was built in order to investigate:Because they are perpendicular to each other, the cyclotron fields are called:The semicircular metal containers of a cyclotron are called:The cyclotron works because the revolution frequency is independent of:Matching the supply frequency to the cyclotron frequency is called the:A small resistance placed in parallel with a galvanometer is called a:Electromagnetic induction was demonstrated by Michael Faraday and:Michael Faraday carried out his experiments in:Joseph Henry carried out his experiments in:Their experiments were conducted around the year:Currents are induced in closed coils by changing:Generating current by varying magnetic fields is called electromagnetic:Asked what use his discovery was, Faraday compared it to a:The SI unit of magnetic flux is the:One weber is the same as one:Magnetic flux is which kind of quantity?Faraday's law says an emf is induced when the flux does what with time?Lenz deduced his rule in the year:Heinrich Friedrich Lenz was a physicist from:Heinrich Lenz lived from 1804 until:Lenz's law says the induced current opposes the change in:What in Faraday's equation represents Lenz's law?Swirling induced currents in a metal plate are called:Who discovered eddy currents?Foucault lived from 1819 until:Eddy current flow patterns are said to resemble swirling eddies in:The SI unit of inductance is the:Certain galvanometers use eddy currents to provide electromagnetic: