Electric and Magnetic Field Analysis MCQs

Q#1: Which law describes the relationship between a static electric charge and the electric field it creates?
(A) Ampère’s Law
(B) Gauss’s Law
(C) Faraday’s Law
(D) Ohm’s Law
Answer: (B) Gauss’s Law

Q#2: The SI unit of electric field intensity is:
(A) Volt
(B) Ampere
(C) Ohm
(D) Volt per meter
Answer: (D) Volt per meter

Q#3: Electric field lines around a point charge:
(A) Originate from the charge and terminate at infinity
(B) Originate from the charge and terminate at another opposite charge
(C) Originate from infinity and terminate at the charge
(D) Originate from two opposite charges and form a closed loop
Answer: (A) Originate from the charge and terminate at infinity

Q#4: According to Gauss’s Law, the electric flux through a closed surface surrounding a charge is proportional to:
(A) The charge enclosed by the surface
(B) The area of the surface
(C) The distance from the charge to the surface
(D) The inverse square of the charge
Answer: (A) The charge enclosed by the surface

Q#5: The electric field inside a conductor in electrostatic equilibrium is:
(A) Zero
(B) Constant
(C) Variable
(D) Infinite
Answer: (A) Zero

Q#6: What is the relationship between electric potential (V) and electric field (E)?
(A) $V = \frac{1}{E}$
(B) $V = E$
(C) $E = \frac{V}{d}$
(D) $E = -\frac{dV}{dr}$
Answer: (D) $E = -\frac{dV}{dr}$

Q#7: Magnetic field lines:
(A) Always form closed loops
(B) Always start from north and end at south poles
(C) Can start or end freely
(D) Are one-dimensional
Answer: (A) Always form closed loops

Q#8: The SI unit of magnetic flux density (magnetic field strength) is:
(A) Tesla
(B) Weber
(C) Gauss
(D) Henry
Answer: (A) Tesla

Q#9: According to Ampère’s Law, the line integral of the magnetic field around a closed loop is proportional to:
(A) The charge enclosed by the loop
(B) The current enclosed by the loop
(C) The magnetic field strength
(D) The area of the loop
Answer: (B) The current enclosed by the loop

Q#10: In a uniform magnetic field, the magnetic force on a moving charged particle is greatest when the particle’s velocity is:
(A) Perpendicular to the magnetic field
(B) Parallel to the magnetic field
(C) Antiparallel to the magnetic field
(D) At an angle of 45 degrees to the magnetic field
Answer: (A) Perpendicular to the magnetic field

Q#11: The right-hand rule for magnetic fields states that if you point your thumb in the direction of the current in a straight wire, the direction of the magnetic field around the wire is:
(A) Toward the thumb
(B) Away from the thumb
(C) Along the fingers
(D) Opposite to the fingers
Answer: (C) Along the fingers

Q#12: Magnetic monopoles, as predicted by theoretical physics, would be:
(A) Particles with only north or south magnetic poles
(B) Particles with electric charges but no magnetic poles
(C) Particles with gravitational poles but no magnetic poles
(D) Non-existent based on current theories
Answer: (D) Non-existent based on current theories

Q#13: The force on a current-carrying conductor in a magnetic field is zero when the angle between the current direction and the magnetic field is:
(A) 0 degrees
(B) 45 degrees
(C) 90 degrees
(D) 180 degrees
Answer: (C) 90 degrees

Q#14: The phenomenon of electromagnetic induction is based on:
(A) The production of magnetic field due to an electric current
(B) The production of electric field due to a changing magnetic field
(C) The generation of both electric and magnetic fields simultaneously
(D) The annihilation of electric and magnetic fields
Answer: (B) The production of electric field due to a changing magnetic field

Q#15: Lenz’s Law is a consequence of which principle?
(A) Conservation of energy
(B) Conservation of charge
(C) Conservation of momentum
(D) Conservation of angular momentum
Answer: (A) Conservation of energy

Q#16: A coil of wire with 500 turns experiences a change in magnetic flux of 0.02 Wb in 0.1 seconds. What is the induced EMF in the coil?
(A) 100 V
(B) 10 V
(C) 5 V
(D) 1 V
Answer: (C) 5 V

Q#17: Mutual induction refers to the phenomenon where:
(A) A changing current in one coil induces a current in another nearby coil
(B) A changing magnetic field induces an electric field in a nearby conductor
(C) Two conductors carry currents in opposite directions
(D) The magnetic field generated by one coil influences the current in the same coil
Answer: (A) A changing current in one coil induces a current in another nearby coil

Q#18: Which material shows the highest magnetic permeability?
(A) Air
(B) Iron
(C) Copper
(D) Aluminum
Answer: (B) Iron

Q#19: In an alternating current (AC) circuit, the impedance of a capacitor:
(A) Increases with frequency
(B) Decreases with frequency
(C) Remains constant with frequency
(D) Is independent of frequency
Answer: (B) Decreases with frequency ✅ (Note: original had “A”, but correct is B)

Q#20: The formula for the self-inductance (L) of a coil is:
(A) $L = \frac{N \Phi}{I}$
(B) $L = \frac{N \Phi}{I}$
(C) $L = \frac{\Phi}{N I}$
(D) $L = \frac{N \Phi}{I}$
Answer: (A) $L = \frac{N \Phi}{I}$

Q#21: A magnetic dipole consists of:
(A) A single north or south magnetic pole
(B) A current loop or a pair of poles
(C) A coil with a varying magnetic field
(D) A material with high magnetic susceptibility
Answer: (B) A current loop or a pair of poles

Q#22: The magnitude of the magnetic force on a moving charged particle is given by:
(A) $F = q v B \sin\theta$
(B) $F = q v B \cos\theta$
(C) $F = \frac{q v B}{\sin\theta}$
(D) $F = \frac{q v B}{\cos\theta}$
Answer: (A) $F = q v B \sin\theta$

Q#23: A current-carrying conductor placed perpendicular to a magnetic field experiences:
(A) Maximum force
(B) Minimum force
(C) No force
(D) Circular motion
Answer: (A) Maximum force

Q#24: Which of the following statements about magnetic shielding is correct?
(A) Magnetic shielding reduces the strength of a magnetic field
(B) Magnetic shielding increases the strength of a magnetic field
(C) Magnetic shielding only affects electric fields
(D) Magnetic shielding is not possible
Answer: (A) Magnetic shielding reduces the strength of a magnetic field

Q#25: The Hall effect is used to measure:
(A) Electric field strength
(B) Magnetic field strength
(C) Electric current
(D) Electron density
Answer: (B) Magnetic field strength

Q#26: The phenomenon of magnetic hysteresis is most commonly associated with:
(A) Ferromagnetic materials
(B) Paramagnetic materials
(C) Diamagnetic materials
(D) Superconducting materials
Answer: (A) Ferromagnetic materials

Q#27: The direction of the magnetic field inside a solenoid carrying current is:
(A) Along the axis of the solenoid, from one end to the other
(B) Along the axis of the solenoid, from the other end to one end
(C) Radially outward from the solenoid
(D) Radially inward toward the axis of the solenoid
Answer: (A) Along the axis of the solenoid, from one end to the other

Q#28: The magnetic flux through a surface is maximum when the angle between the magnetic field and the normal to the surface is:
(A) 0 degrees
(B) 45 degrees
(C) 90 degrees
(D) 180 degrees
Answer: (A) 0 degrees

Q#29: The unit of magnetic pole strength (magnetic moment) is:
(A) Tesla
(B) Weber
(C) Ampere-turn meter
(D) Weber per square meter
Answer: (C) Ampere-turn meter

Q#30: In a cyclotron, charged particles are accelerated using:
(A) Electric fields
(B) Magnetic fields
(C) Both electric and magnetic fields
(D) Gravitational fields
Answer: (C) Both electric and magnetic fields