Free Electromagnetism MCQs with Answers

• A. zero resistance
• B. infinite resistance
• C. small resistance
• D. intermediate resistance

Explanation: B is the correct answer. When a galvanometer used as an ohmmeter gives full deflection, it indicates that the resistance in the circuit is…

• A. north pole
• B. south pole
• C. neutral
• D. we cannot predict about it

Explanation: B is the correct answer. When the north pole of a magnet is moved towards the face of a coil, it induces a current in the coil.

• A. galvanometer
• B. DC generator
• C. transformer
• D. AC generator

Explanation: B is the correct answer. The construction of a DC motor is similar to that of a DC generator.

• A. AC generator
• B. DC generator
• C. DC motor
• D. both b and c

Explanation: D is the correct answer. Commutators are used in both DC generators and DC motors to ensure that the direction of the current in the…

• A. eddy current
• B. magnetic hysteresis
• C. resistance of coils
• D. all

Explanation: D is the correct answer. The loss of power in a transformer is due to various factors, including eddy current losses, magnetic hysteresis…

• A. Capacitor: Electric field; Inductor: Electric field
• B. Capacitor: Magnetic field; Inductor: Magnetic Field
• C. Capacitor: Electric field; Inductor: Magnetic field
• D. Capacitor: Magnetic field; Inductor: Electric field

Explanation: C is the correct answer.In a capacitor, energy is stored in the electric field between its plates.

• A. parallel to magnetic field
• B. perpendicular to magnetic field
• C. inclined at 45° to magnetic field
• D. inclined at 60° to magnetic field

Explanation: B is the correct answer.The torque experienced by a current carrying coil in a magnetic field is given by the formula τ=NIABsinθ, where N…

• A. stronger to weak field
• B. weak to strong field
• C. strong to weak if current is large
• D. weak to strong if current is large

Explanation: B is the correct answer.According to Fleming's left-hand rule, when a current carrying conductor is placed in a magnetic field, a force is…

• A. parallel to the field
• B. opposite to the field
• C. parallel to its direction
• D. perpendicular to both the field and velocity vector

Explanation: D is the correct answerThe direction of the force experienced by a charged particle moving in a magnetic field is given by the right-hand…

• A. 9.43 x 10^-19C/kg
• B. 9.43 x 10^-31C/kg
• C. 1.76 x 10^11C/kg
• D. 9.43 x 10^-27 C/kg

Explanation: C is the correct answerThe value c/m represents the charge-to-mass ratio of an electron. It is approximately 9.43×10^−31 C/kg.

• A. range switch
• B. power switch
• C. selective switch
• D. all of these

Explanation: A is the correct answer.an AVO meter, the range switch is used to select different measurement ranges for current, voltage, or resistance.

• A. increases with the increase in the field strength
• B. decreases with the increase in the field strength
• C. is always zero
• D. depends upon whether the field is uniform or non-uniform

Explanation: C is the correct answer. The magnetic field does not do any work on a charged particle.

• A. anl
• B. nl
• C. nI/a
• D. n^2l

Explanation: B is the correct answer. The magnetic field B inside a long solenoid is directly proportional to the number of turns per unit length n and…

• A. North
• B. South
• C. East
• D. West

Explanation: B is the correct answer. According to the right-hand rule, if a current-carrying conductor is placed in a magnetic field, the direction of…

• A. Slip rings
• B. Armature
• C. Commutator
• D. Electromagnet

Explanation: B is the correct answer.The number of coils wound around an iron cylinder, which is rotated in a magnetic field to induce an electromotive…

• A. Tri-polar generator
• B. Multipolar generator
• C. Dipolar generator
• D. Homopolar generator

Explanation: D is the correct answer.Faraday's homopolar generator is the one with which he was able to produce continuous induced current.

• A. M^OL^OT^0
• B. M°L^0T
• C. MLT^2
• D. M^2L^0T^2

Explanation: A is the correct answerThe dimensional formula for inductance (L) is M^1L^2T^−2I^−2, and the dimensional formula for resistance (R) is…

• A. The rate of transmission is faster at high voltage
• B. It is more economical due to less power loss
• C. Power cannot be transmitted at low voltages
• D. A precaution against theft of transmission lines

Explanation: B is the correct answer A.C. power is transmitted at high voltage because it reduces the current flowing through the transmission lines.

• A. Self inductance
• B. Mutual inductance
• C. Self induction
• D. Mutual induction

Explanation: A is the correct answer. The ratio of the average induced emf to the rate of change of current in the coil is known as self inductance.

• A. using a stronger magnetic field
• B. moving the loop faster
• C. replacing loop by a coil of many turns
• D. all of these

Explanation: D is the correct answer.The induced current in a loop can be increased by increasing the strength of the magnetic field, increasing the…