AP EAPCET (Engineering) Moving Charges and Magnetism — practice questions
119 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice AP EAPCET (Engineering) Moving Charges and Magnetism in the app →A circular coil of radius $R$ carries current $I$. The magnetic field at the centre of the coil is:Magnetic field is measured in:Biot Savart law gives magnetic field due to a current element. It states dB is proportional to:The magnetic force on a charge q moving with velocity v in field B:A current-carrying wire of length L in magnetic field B experiences force:Ampere's law states the line integral of B around a closed loop equals:A magnetic dipole moment of a current loop is:Magnetic field at center of a circular loop of radius R carrying current I:Magnetic field inside a long solenoid (n turns per unit length, current I):Magnetic field at distance r from a long straight current-carrying wire:A charged particle of charge q, mass m enters magnetic field B perpendicular to velocity v. It follows a:Torque on a current loop (moment m) in uniform field B:In a velocity selector, electric field E and magnetic field B are perpendicular. Velocity of particles passingMagnetic field on the axis of a circular loop at distance x from center:Magnetic flux through a surface is:Cyclotron frequency for a charged particle in magnetic field B:A solenoid of 200 turns, length 0.5 m, carries 2 A. Find magnetic field inside (μ₀ = 4π × 10⁻⁷):A charged particle moves in a circle of radius 2 cm in a 1 T magnetic field with speed 4 × 10⁶ m/s. Mass-to-chFor a current loop in a non-uniform magnetic field, net force is zero only if:Earth's magnetic field is approximately 50 μT. Force on a 1 m wire carrying 10 A perpendicular to field:A toroid with 1000 turns and average radius 10 cm carries 0.5 A current. Field inside:Two parallel wires carrying currents in OPPOSITE directions:A magnetic dipole of moment m in field B has potential energy:Oersted's 1820 demonstration showed a current deflecting which object?In which year did Oersted observe a current deflecting a compass needle?Oersted concluded that a magnetic field is produced by what?Which physicist realised that light is an electromagnetic wave after unifying electricity and magnetism?A charge moving parallel to a magnetic field feels what magnetic force?In which direction does the magnetic force on a moving charge act?One gauss, the smaller non-SI unit of magnetic field, equals how many tesla?Which combination of units is equivalent to one tesla?A 0.5 m wire carrying 4 A is at 30° to a 0.2 T field. Force on it?An electron moves at 2 × 10^6 m/s perpendicular to a 0.5 T field. Force on it?Why does a magnetic field do no work on a moving charge?If a charge's velocity has a component along B, its path isRadius of the circular path of charge q, mass m, speed v in field B isDoubling a charged particle's speed in a fixed field changes its orbit radius how?The frequency of circular motion of a charge in B is independent ofIf B doubles, how does the orbital frequency of a given charge change?What property of circular motion in B does a cyclotron exploit?The distance a helically moving charge advances along B in one rotation is called itsAn electron moving at 3 × 10^7 m/s has a kinetic energy of aboutIn the Biot-Savart law, the magnitude of dB varies with distance r asThe Biot-Savart law gives the magnetic field due to which source?The Biot-Savart field dB at a point along the line of the current element isWhich relation links μ0, ε0 and the speed of light c?How do the Coulomb and Biot-Savart fields both depend on distance?The Biot-Savart field dB at point P points in which direction?A single loop of radius 10 cm carries 5 A. Field at its centre?A long straight wire carries 10 A. What is the field 5 cm from it?Ampere's circuital law: loop integral of B equalsThe closed contour chosen when applying Ampere's law is called aIf the net current enclosed by an Amperian loop is zero, the line integral of B isThe field outside an ideal very long solenoid is taken to beInside a long solenoid the magnetic field isWhy are enamelled wires used to wind a solenoid?What does a soft iron core inside a solenoid do to the field?The equal and opposite forces on two parallel current-carrying wires agree withForce per unit length between parallel currents Ia and Ib a distance d apart isWires 0.1 m apart carry 10 A and 20 A in parallel. Force per metre?The ampere definition uses long parallel wires placed how far apart?Which instrument is used to measure the force between current-carrying coils in practice?One coulomb of charge crosses a conductor's section in 1 s at what current?A loop of area A carrying I has B in its plane. The torque isA 100-turn, 0.01 m^2 coil with 2 A lies in the plane of a 0.5 T field. Torque?The magnetic moment of a planar loop with N turns, current I, area A isA 50-turn coil of area 0.04 m^2 carries 0.2 A. Its magnetic moment?Seen from far away, a planar current loop is equivalent toOn the axis of a circular loop far away (x much greater than R), B varies asWhich isolated entity has never been observed, unlike electric charge?Ampere suggested that all magnetism arises fromA moving coil galvanometer gets its radial field usingIn a moving coil galvanometer, what balances the magnetic torque?The deflection of a moving coil galvanometer is proportional toA 100 ohm, 1 mA galvanometer becomes a 10 V voltmeter. Series resistance?Doubling the coil turns N in a galvanometer does what to current sensitivity?If the turns N in a galvanometer coil are doubled, voltage sensitivityRoughly how strong is the earth's magnetic field at its surface?A charged particle moves in a region with only a uniform magnetic field. What happens to its kinetic energy?In helical motion in a magnetic field, the distance moved along the field in one rotation is called theIn the definition of the ampere, each of two long parallel wires 1 m apart experiences what force per metre?A solenoid has 1000 turns per metre and carries 2 A. What is the field inside it? (mu0 = 4 pi x 10^-7)A galvanometer becomes an ammeter when we connect aA 100-turn coil of area 0.01 m^2 carries 0.5 A, with its plane parallel to a 0.4 T field. What is the torque?What is the net force on a current loop placed in a uniform magnetic field?The magnetic moment of a current loop points along the direction given by theA proton (m = 1.67 x 10^-27 kg) circles in a 1 T field. What is its frequency?If a charge's speed is doubled while it circles in the same field, its orbit radiusWires carrying 10 A and 5 A lie 0.1 m apart in parallel. What is the force per metre?A solenoid of 500 turns and length 0.5 m carries 4 A. What is the central field?The current sensitivity of a galvanometer is defined as deflection per unitWhich Danish physicist noticed a compass needle deflect near a current-carrying wire?A proton moves along +x in a field along +y. The magnetic force on it points alongIn the Biot-Savart law, the field from a current element varies with distance r roughly asThe cyclotron is a machine used toThe Lorentz force on a charge in electric and magnetic fields is given byIn a galvanometer, spring torque balances magnetic torque, so deflection is proportional toA galvanometer of 100 ohm, full scale 1 mA, is to read 1 A. Shunt needed is aboutIf the magnetic field is doubled, the time period of a charge circling in itA charge enters a uniform field at an angle that is neither 0 nor 90 degrees to it. Its path isAmpere's circuital law is to the Biot-Savart law as which law is to Coulomb's law?An alpha particle and a proton enter a field at equal speed. The ratio of their radii (alpha : proton) isThe permeability of free space has the valueThe Lorentz force is exerted on a charged particle by which fields?The magnetic part of the Lorentz force on a charge is directed how?The magnetic force on a current-carrying wire is sometimes given what name?In which year did Hendrik Lorentz arrive at a complete derivation of the force law?Who correctly identified the contribution of the magnetic force before Lorentz's full derivation?Who first described the cyclotron concept in print in Science in 1930?Lawrence conceived the cyclotron after reading a paper on which device by Rolf Wideroe?A cyclotron is essentially a linear accelerator arranged in what form?In a cyclotron, what makes the particles orbit?The cyclotron design is more space efficient than a linear accelerator because of what?Space charge in a cyclotron beam refers to which effect?Which isotope made in cyclotrons is used for PET imaging?Cyclotron beams in particle therapy are mainly used to treat which condition?Which type of particle beam are cyclotrons primarily used for in radiotherapy?What did Lawrence invent from the cyclotron design during the Manhattan Project?In 1946 Lawrence's team built an early version of which cyclotron type?