GUJCET Electromagnetism — practice questions
98 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice GUJCET Electromagnetism in the app →Two point charges of $+4\ \mu$C each are separated by $0.6$ m in vacuum. The magnitude of the electrostatic foWhat is the electric field at the centre of a hollow conducting sphere of radius $R$ carrying total charge $Q$A parallel-plate capacitor has capacitance $C_0$ in vacuum. A dielectric slab of dielectric constant $K = 4$ iTwo capacitors of $6\ \mu$F and $3\ \mu$F are connected in series across a $12$ V battery. What is the equivalAn electric dipole of moment $p$ is placed at $60°$ to a uniform electric field of magnitude $E$. The torque oA point charge $+q$ is placed at the centre of a cube. What is the electric flux through one face of the cube?
Oersted's experiment demonstrated that:The magnetic field at a perpendicular distance $r$ from a long straight current-carrying wire of current $I$ iA circular coil of radius $R$ carries current $I$. The magnetic field at the centre of the coil is:Two long, parallel wires carry currents $I_1$ and $I_2$ in the **same direction** separated by distance $d$. TA charged particle moves perpendicular to a uniform magnetic field $B$ with speed $v$. The radius of its circuGauss's law for electric flux through a closed surface enclosing total charge $q$ is:The electric field intensity at any point **inside** a uniformly charged hollow conducting sphere is:The SI unit of capacitance is:Electrostatic potential due to a point charge $q$ at distance $r$ in vacuum is:An electric dipole of moment $\vec p$ is placed in a uniform external field $\vec E$. The torque on it is:Under electrostatic equilibrium, the net electric field in the **interior** of a conductor is:An equipotential surface in any electric field is:When $n$ identical capacitors of capacitance $C$ are connected in series, the equivalent capacitance is:A delicate galvanometer placed inside a sealed metal box is unaffected by a strong external electric field. ThThe dipole moment $\vec p$ of a pair of charges $+q$ and $-q$ separated by $2\ell$ is directed:Using Gauss's law for an infinitely long straight wire with linear charge density $\lambda$, the electric fielFor an infinite plane sheet carrying uniform surface charge density $ igma$, the magnitude of the electric fieA thin wire is bent into a circular ring of radius 10 cm. A charge of 250 μC spreads uniformly over it. The elTwo equal charges of $3 \times 10^{-5}$ C each are brought from infinity to a separation of 30 cm. The electroThe equipotential surfaces shown are around an isolated point charge. The shape and behaviour of these surfaceThe figure shows equipotential surfaces in a region of uniform electric field. The correct interpretation is:
Three capacitors of 4 μF each are connected: two in parallel, that combination in series with the third. The eA parallel-plate air capacitor has capacitance $C_0$. A dielectric slab of dielectric constant $k$ is insertedWhich of the following molecules is **non-polar** (has zero permanent dipole moment)?For a linear isotropic dielectric, the polarization $\vec P$ produced by an applied field $\vec E$ is:A short dipole of moment $p = 1 \times 10^{-9}$ C·m. The electric potential due to it at 0.3 m from the centreWork done in moving a 6 C charge between two points raises the system's potential energy by 120 J. If the starTwo charges $5 \times 10^{-8}$ C and $-3 \times 10^{-8}$ C are placed 16 cm apart on the x-axis (positive charFour charges $+q$, $-q$, $+q$, $-q$ are placed at the corners of a square of side $r$ in cyclic order. The eleA charged particle carrying $-1.6 \times 10^{-19}$ C is held in equilibrium against gravity between two horizoA spherical capacitor consists of two concentric conducting shells of inner radius $a$ and outer radius $b$. IA cylindrical capacitor consists of two coaxial conducting cylinders of length $l$ and radii $a$ (inner) and $An electric dipole of moment $p = 2 \times 10^{-8}$ C·m is placed in a uniform field $E = 10^5$ N/C. The work A dielectric slab of thickness $t$ and dielectric constant $k$ is introduced between the plates of a parallel-Two charges, $5$ nC at $(2\,\text{cm},0,0)$ and $-2$ nC at $(20\,\text{cm},0,0)$, are placed in free space witThe SI unit of electric charge is the:Coulomb's law: force between two point charges is proportional to:The value of k in Coulomb's law (in SI) is approximately:Electric field strength at a point is defined as force per unit:Total electric flux through a closed surface enclosing charge q (Gauss's law) is:Electric field due to an INFINITE SHEET of charge with surface charge density σ:The principle that charge can be neither created nor destroyed is:Two point charges +2μC and -3μC are separated by 30 cm. The force on each (k = 9 × 10⁹):Electric field due to a point charge q at distance r:A charge of 1 C placed in an electric field of 100 N/C experiences force:Electric potential V due to point charge q at distance r:Potential difference between two points is 12 V. Work done to move 2 C between them:Electric field INSIDE a conductor in electrostatic equilibrium is:At an axial point of an electric dipole at distance r >> a (a = dipole half-length, p = qa·2 the dipole momentNumber of charges that can be enclosed in a Gaussian surface in vacuum:For a parallel plate capacitor with plate area A and separation d, the capacitance in vacuum:Capacitance changes when DIELECTRIC of relative permittivity K is inserted:Energy stored in a capacitor with charge Q and capacitance C:Two charges +q and +q are placed at corners of an equilateral triangle. The third corner has potential:For a spherical conductor of radius R carrying charge Q, the potential AT THE SURFACE equals:Equipotential surfaces around a point charge are:Two capacitors 2 µF and 4 µF connected in SERIES across 12 V. Charge on each:3 capacitors of 6 µF each in PARALLEL: total capacitance:Two charged spheres each of radius R, charge Q, separated by distance d >> R. Force F between them is:Potential at center of square (side a) with charges +q, -q, +q, -q at corners (alternating):Electric field inside a spherical cavity in a uniformly charged conductor is:Find work done to bring a +2 µC charge from infinity to a point where V = 50 V:A charged particle q is held at rest in vertical equilibrium in a uniform electric field E pointing upward. ChIn a capacitor circuit, when a dielectric is inserted while voltage is HELD CONSTANT by battery, the CHARGE onMagnetic 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:Two parallel wires 1 m apart carry currents I1 = 2 A and I2 = 3 A in the SAME direction. Force per unit lengthTorque 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:A proton (mass m, charge e) enters a uniform magnetic field B perpendicular to its velocity v. Time to completCyclotron frequency for a charged particle in magnetic field B:An electron beam moves with velocity v in a region with E perpendicular to v. To pass undeflected, magnetic fiA 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-chIn a hydrogen atom, the magnetic moment associated with electron orbital motion in ground state is approximateFor 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:A solenoid is also called an 'electromagnet'. Why does inserting an iron core greatly increase its magnetic fiTwo parallel wires carrying currents in OPPOSITE directions:A magnetic dipole of moment m in field B has potential energy:In a mass spectrometer, ions of same charge but different mass enter perpendicular to uniform B with same velo